tcsh - C shell with file name completion and command line editing


   tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
   tcsh -l


   tcsh  is  an enhanced but completely compatible version of the Berkeley
   UNIX C shell, csh(1).  It is a command language interpreter usable both
   as an interactive login shell and a shell script command processor.  It
   includes  a  command-line  editor  (see   The   command-line   editor),
   programmable  word  completion  (see  Completion and listing), spelling
   correction (see Spelling correction), a history mechanism (see  History
   substitution),  job  control  (see  Jobs) and a C-like syntax.  The NEW
   FEATURES section describes major  enhancements  of  tcsh  over  csh(1).
   Throughout  this  manual,  features  of  tcsh  not found in most csh(1)
   implementations (specifically, the 4.4BSD csh) are labeled with  `(+)',
   and features which are present in csh(1) but not usually documented are
   labeled with `(u)'.

   Argument list processing
   If the first argument (argument 0) to the shell is `-'  then  it  is  a
   login shell.  A login shell can be also specified by invoking the shell
   with the -l flag as the only argument.

   The rest of the flag arguments are interpreted as follows:

   -b  Forces a ``break'' from  option  processing,  causing  any  further
       shell  arguments  to  be  treated  as  non-option  arguments.   The
       remaining arguments will not be interpreted as shell options.  This
       may  be used to pass options to a shell script without confusion or
       possible subterfuge.  The shell will not run a set-user  ID  script
       without this option.

   -c  Commands  are  read  from  the  following  argument  (which must be
       present, and must be a single  argument),  stored  in  the  command
       shell   variable   for  reference,  and  executed.   Any  remaining
       arguments are placed in the argv shell variable.

   -d  The shell loads the directory stack from  ~/.cshdirs  as  described
       under Startup and shutdown, whether or not it is a login shell. (+)

       Sets the environment variable name to value. (Domain/OS only) (+)

   -e  The  shell  exits  if  any invoked command terminates abnormally or
       yields a non-zero exit status.

   -f  The shell does not load any resource or startup files,  or  perform
       any command hashing, and thus starts faster.

   -F  The shell uses fork(2) instead of vfork(2) to spawn processes. (+)

   -i  The  shell is interactive and prompts for its top-level input, even
       if it appears to not be a terminal.  Shells are interactive without
       this option if their inputs and outputs are terminals.

   -l  The shell is a login shell.  Applicable only if -l is the only flag

   -m  The shell loads ~/.tcshrc  even  if  it  does  not  belong  to  the
       effective  user.  Newer versions of su(1) can pass -m to the shell.

   -n  The shell parses commands but does not execute them.  This aids  in
       debugging shell scripts.

   -q  The shell accepts SIGQUIT (see Signal handling) and behaves when it
       is used under a debugger.  Job control is disabled. (u)

   -s  Command input is taken from the standard input.

   -t  The shell reads and executes a single line of input.  A `\' may  be
       used  to  escape  the  newline at the end of this line and continue
       onto another line.

   -v  Sets the verbose shell variable, so that command  input  is  echoed
       after history substitution.

   -x  Sets   the  echo  shell  variable,  so  that  commands  are  echoed
       immediately before execution.

   -V  Sets the verbose shell variable even before executing ~/.tcshrc.

   -X  Is to -x as -V is to -v.

       Print a help message on the standard output and exit. (+)

       Print the  version/platform/compilation  options  on  the  standard
       output and exit.  This information is also contained in the version
       shell variable. (+)

   After processing of flag arguments, if arguments remain but none of the
   -c,  -i,  -s,  or -t options were given, the first argument is taken as
   the name of a file of commands, or ``script'',  to  be  executed.   The
   shell opens this file and saves its name for possible resubstitution by
   `$0'.  Because many systems  use  either  the  standard  version  6  or
   version  7  shells  whose  shell  scripts  are not compatible with this
   shell, the shell uses such a `standard' shell to execute a script whose
   first character is not a `#', i.e., that does not start with a comment.

   Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
   A  login  shell  begins  by  executing  commands  from the system files
   /etc/csh.cshrc and /etc/csh.login.   It  then  executes  commands  from
   files  in  the  user's  home  directory:  first  ~/.tcshrc  (+)  or, if
   ~/.tcshrc is not found, ~/.cshrc, then ~/.history (or the value of  the
   histfile shell variable), then ~/.login, and finally ~/.cshdirs (or the
   value of  the  dirsfile  shell  variable)  (+).   The  shell  may  read
   /etc/csh.login  before  instead  of  after /etc/csh.cshrc, and ~/.login
   before instead of after ~/.tcshrc or ~/.cshrc  and  ~/.history,  if  so
   compiled; see the version shell variable. (+)

   Non-login  shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on

   For     examples     of     startup     files,      please      consult

   Commands  like  stty(1)  and  tset(1),  which need be run only once per
   login, usually go in one's ~/.login file.  Users who need  to  use  the
   same  set  of  files with both csh(1) and tcsh can have only a ~/.cshrc
   which checks for the existence of the tcsh shell variable (q.v.) before
   using  tcsh-specific  commands,  or  can  have  both  a  ~/.cshrc and a
   ~/.tcshrc which sources (see the builtin command) ~/.cshrc.   The  rest
   of  this manual uses `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is
   not found, ~/.cshrc'.

   In the  normal  case,  the  shell  begins  reading  commands  from  the
   terminal, prompting with `> '.  (Processing of arguments and the use of
   the shell to process files containing  command  scripts  are  described
   later.)   The shell repeatedly reads a line of command input, breaks it
   into words, places it on  the  command  history  list,  parses  it  and
   executes each command in the line.

   One can log out by typing `^D' on an empty line, `logout' or `login' or
   via  the  shell's  autologout  mechanism  (see  the  autologout   shell
   variable).   When  a  login  shell  terminates it sets the logout shell
   variable to `normal'  or  `automatic'  as  appropriate,  then  executes
   commands  from  the files /etc/csh.logout and ~/.logout.  The shell may
   drop DTR on logout if so compiled; see the version shell variable.

   The names of the system login and logout  files  vary  from  system  to
   system for compatibility with different csh(1) variants; see FILES.

   We  first describe The command-line editor.  The Completion and listing
   and Spelling correction sections describe  two  sets  of  functionality
   that  are  implemented  as  editor commands but which deserve their own
   treatment.  Finally, Editor commands lists  and  describes  the  editor
   commands specific to the shell and their default bindings.

   The command-line editor (+)
   Command-line  input  can  be edited using key sequences much like those
   used in GNU Emacs or vi(1).  The editor is active only  when  the  edit
   shell  variable  is  set, which it is by default in interactive shells.
   The bindkey builtin can display and change key  bindings.   Emacs-style
   key  bindings  are  used  by  default  (unless  the  shell was compiled
   otherwise; see the version shell variable), but bindkey can change  the
   key bindings to vi-style bindings en masse.

   The  shell  always  binds  the  arrow  keys  (as defined in the TERMCAP
   environment variable) to

       down    down-history
       up      up-history
       left    backward-char
       right   forward-char

   unless doing so would alter another single-character binding.  One  can
   set  the  arrow  key escape sequences to the empty string with settc to
   prevent these bindings.  The ANSI/VT100 sequences for  arrow  keys  are
   always bound.

   Other  key  bindings are, for the most part, what Emacs and vi(1) users
   would expect and can easily be displayed by bindkey,  so  there  is  no
   need to list them here.  Likewise, bindkey can list the editor commands
   with a short description of each.

   Note that editor commands do not have the same notion of a ``word''  as
   does  the  shell.   The editor delimits words with any non-alphanumeric
   characters not  in  the  shell  variable  wordchars,  while  the  shell
   recognizes  only  whitespace  and  some  of the characters with special
   meanings to it, listed under Lexical structure.

   Completion and listing (+)
   The shell  is  often  able  to  complete  words  when  given  a  unique
   abbreviation.  Type part of a word (for example `ls /usr/lost') and hit
   the tab key  to  run  the  complete-word  editor  command.   The  shell
   completes the filename `/usr/lost' to `/usr/lost+found/', replacing the
   incomplete word with the complete word in the input buffer.  (Note  the
   terminal `/'; completion adds a `/' to the end of completed directories
   and a space to the end of other completed words, to  speed  typing  and
   provide  a  visual  indicator  of successful completion.  The addsuffix
   shell variable can be unset to prevent this.)  If  no  match  is  found
   (perhaps `/usr/lost+found' doesn't exist), the terminal bell rings.  If
   the word is already complete (perhaps there is a  `/usr/lost'  on  your
   system,  or perhaps you were thinking too far ahead and typed the whole
   thing) a `/' or space is added to the end if it isn't already there.

   Completion works anywhere in the line, not at just the  end;  completed
   text  pushes  the  rest  of  the  line to the right.  Completion in the
   middle of a word often results in leftover characters to the  right  of
   the cursor that need to be deleted.

   Commands  and  variables  can  be  completed in much the same way.  For
   example, typing `em[tab]' would complete `em' to `emacs' if emacs  were
   the  only  command  on your system beginning with `em'.  Completion can
   find a command in any directory in path or if given  a  full  pathname.
   Typing  `echo  $ar[tab]'  would  complete  `$ar' to `$argv' if no other
   variable began with `ar'.

   The shell parses the input buffer to determine  whether  the  word  you
   want  to  complete  should  be  completed  as  a  filename,  command or
   variable.  The first word in the buffer and the  first  word  following
   `;',  `|',  `|&',  `&&'  or `||' is considered to be a command.  A word
   beginning with `$' is considered to be a variable.  Anything else is  a
   filename.  An empty line is `completed' as a filename.

   You  can  list the possible completions of a word at any time by typing
   `^D' to run the delete-char-or-list-or-eof editor command.   The  shell
   lists  the  possible  completions  using  the  ls-F builtin (q.v.)  and
   reprints the prompt and unfinished command line, for example:

       > ls /usr/l[^D]
       lbin/       lib/        local/      lost+found/
       > ls /usr/l

   If the autolist shell variable is set, the shell  lists  the  remaining
   choices (if any) whenever completion fails:

       > set autolist
       > nm /usr/lib/libt[tab]
       libtermcap.a@ libtermlib.a@
       > nm /usr/lib/libterm

   If  autolist  is  set  to  `ambiguous',  choices  are  listed only when
   completion  fails  and  adds  no  new  characters  to  the  word  being

   A  filename  to be completed can contain variables, your own or others'
   home directories abbreviated with `~' (see Filename  substitution)  and
   directory  stack  entries  abbreviated  with  `='  (see Directory stack
   substitution).  For example,

       > ls ~k[^D]
       kahn    kas     kellogg
       > ls ~ke[tab]
       > ls ~kellogg/


       > set local = /usr/local
       > ls $lo[tab]
       > ls $local/[^D]
       bin/ etc/ lib/ man/ src/
       > ls $local/

   Note that variables can also be expanded explicitly  with  the  expand-
   variables editor command.

   delete-char-or-list-or-eof  lists  at  only the end of the line; in the
   middle of a line it deletes the character under the cursor  and  on  an
   empty  line  it  logs  one  out  or, if ignoreeof is set, does nothing.
   `M-^D', bound to the  editor  command  list-choices,  lists  completion
   possibilities  anywhere  on a line, and list-choices (or any one of the
   related editor commands that do or don't delete, list and/or  log  out,
   listed  under delete-char-or-list-or-eof) can be bound to `^D' with the
   bindkey builtin command if so desired.

   The complete-word-fwd and complete-word-back editor commands (not bound
   to  any  keys  by default) can be used to cycle up and down through the
   list of possible completions, replacing the current word with the  next
   or previous word in the list.

   The  shell  variable  fignore  can  be  set to a list of suffixes to be
   ignored by completion.  Consider the following:

       > ls
       Makefile        condiments.h~   main.o          side.c
       README          main.c          meal            side.o
       condiments.h    main.c~
       > set fignore = (.o \~)
       > emacs ma[^D]
       main.c   main.c~  main.o
       > emacs ma[tab]
       > emacs main.c

   `main.c~' and `main.o' are ignored by  completion  (but  not  listing),
   because they end in suffixes in fignore.  Note that a `\' was needed in
   front of `~' to prevent it from being expanded  to  home  as  described
   under Filename substitution.  fignore is ignored if only one completion
   is possible.

   If the complete shell variable  is  set  to  `enhance',  completion  1)
   ignores  case  and  2) considers periods, hyphens and underscores (`.',
   `-' and `_') to be word separators and hyphens and  underscores  to  be
   equivalent.  If you had the following files

       comp.lang.c      comp.lang.perl   comp.std.c++
       comp.lang.c++    comp.std.c

   and  typed  `mail  -f  c.l.c[tab]',  it  would be completed to `mail -f
   comp.lang.c', and ^D  would  list  `comp.lang.c'  and  `comp.lang.c++'.
   `mail  -f  c..c++[^D]'  would  list `comp.lang.c++' and `comp.std.c++'.
   Typing `rm a--file[^D]' in the following directory

       A_silly_file    a-hyphenated-file    another_silly_file

   would list all three files, because case is  ignored  and  hyphens  and
   underscores  are  equivalent.   Periods, however, are not equivalent to
   hyphens or underscores.

   If the complete shell variable is set to `Enhance', completion  ignores
   case  and differences between a hyphen and an underscore word separator
   only when the user types a lowercase character or a  hyphen.   Entering
   an   uppercase   character   or   an  underscore  will  not  match  the
   corresponding lowercase character or hyphen word separator.  Typing `rm
   a--file[^D]'  in the directory of the previous example would still list
   all  three  files,  but  typing   `rm   A--file'   would   match   only
   `A_silly_file'   and   typing   `rm   a__file[^D]'   would  match  just
   `A_silly_file' and `another_silly_file'  because  the  user  explicitly
   used an uppercase or an underscore character.

   Completion  and  listing are affected by several other shell variables:
   recexact can be set to complete on the shortest possible unique  match,
   even if more typing might result in a longer match:

       > ls
       fodder   foo      food     foonly
       > set recexact
       > rm fo[tab]

   just beeps, because `fo' could expand to `fod' or `foo', but if we type
   another `o',

       > rm foo[tab]
       > rm foo

   the completion completes on `foo', even though `food' and `foonly' also
   match.   autoexpand can be set to run the expand-history editor command
   before each completion attempt, autocorrect can  be  set  to  spelling-
   correct  the word to be completed (see Spelling correction) before each
   completion  attempt  and  correct  can  be  set  to  complete  commands
   automatically  after  one  hits `return'.  matchbeep can be set to make
   completion beep or not beep in a variety of situations, and nobeep  can
   be  set  to  never  beep  at  all.   nostat  can  be  set  to a list of
   directories and/or patterns  that  match  directories  to  prevent  the
   completion  mechanism  from  stat(2)ing those directories.  listmax and
   listmaxrows  can  be  set  to  limit  the  number  of  items  and  rows
   (respectively)     that    are    listed    without    asking    first.
   recognize_only_executables can be set  to  make  the  shell  list  only
   executables when listing commands, but it is quite slow.

   Finally, the complete builtin command can be used to tell the shell how
   to  complete  words  other  than  filenames,  commands  and  variables.
   Completion  and  listing  do  not  work  on glob-patterns (see Filename
   substitution),  but  the  list-glob  and  expand-glob  editor  commands
   perform equivalent functions for glob-patterns.

   Spelling correction (+)
   The shell can sometimes correct the spelling of filenames, commands and
   variable names as well as completing and listing them.

   Individual words can be spelling-corrected with the  spell-word  editor
   command (usually bound to M-s and M-S) and the entire input buffer with
   spell-line (usually bound to M-$).  The correct shell variable  can  be
   set to `cmd' to correct the command name or `all' to correct the entire
   line each time return is typed, and autocorrect can be set  to  correct
   the word to be completed before each completion attempt.

   When  spelling correction is invoked in any of these ways and the shell
   thinks that any part of the command line is misspelled, it prompts with
   the corrected line:

       > set correct = cmd
       > lz /usr/bin
       CORRECT>ls /usr/bin (y|n|e|a)?

   One can answer `y' or space to execute the corrected line, `e' to leave
   the uncorrected command in the input buffer, `a' to abort  the  command
   as if `^C' had been hit, and anything else to execute the original line

   Spelling  correction  recognizes  user-defined  completions  (see   the
   complete  builtin command).  If an input word in a position for which a
   completion is defined resembles a word in the completion list, spelling
   correction  registers  a  misspelling and suggests the latter word as a
   correction.  However, if the input word  does  not  match  any  of  the
   possible  completions  for  that position, spelling correction does not
   register a misspelling.

   Like completion,  spelling  correction  works  anywhere  in  the  line,
   pushing  the  rest  of the line to the right and possibly leaving extra
   characters to the right of the cursor.

   Beware: spelling correction is not  guaranteed  to  work  the  way  one
   intends,   and   is   provided   mostly  as  an  experimental  feature.
   Suggestions and improvements are welcome.

   Editor commands (+)
   `bindkey' lists  key  bindings  and  `bindkey  -l'  lists  and  briefly
   describes  editor  commands.  Only new or especially interesting editor
   commands are described here.  See emacs(1) and vi(1)  for  descriptions
   of each editor's key bindings.

   The  character  or characters to which each command is bound by default
   is given in parentheses.  `^character' means a  control  character  and
   `M-character'  a meta character, typed as escape-character on terminals
   without a meta key.  Case  counts,  but  commands  that  are  bound  to
   letters  by  default are bound to both lower- and uppercase letters for

   complete-word (tab)
           Completes a word as described under Completion and listing.

   complete-word-back (not bound)
           Like complete-word-fwd, but steps up from the end of the list.

   complete-word-fwd (not bound)
           Replaces the current word with the first word in  the  list  of
           possible completions.  May be repeated to step down through the
           list.  At the end  of  the  list,  beeps  and  reverts  to  the
           incomplete word.

   complete-word-raw (^X-tab)
           Like complete-word, but ignores user-defined completions.

   copy-prev-word (M-^_)
           Copies  the  previous  word  in the current line into the input
           buffer.  See also insert-last-word.

   dabbrev-expand (M-/)
           Expands the current word to the most recent preceding  one  for
           which  the  current is a leading substring, wrapping around the
           history list (once)  if  necessary.   Repeating  dabbrev-expand
           without  any  intervening  typing  changes to the next previous
           word etc., skipping identical matches much like history-search-
           backward does.

   delete-char (bound to `Del' if using the standard /etc/csh.cshrc)
           Deletes  the character under the cursor.  See also delete-char-

   delete-char-or-eof (not bound)
           Does delete-char if there is a character under  the  cursor  or
           end-of-file on an empty line.  See also delete-char-or-list-or-

   delete-char-or-list (not bound)
           Does delete-char if there is a character under  the  cursor  or
           list-choices  at the end of the line.  See also delete-char-or-

   delete-char-or-list-or-eof (^D)
           Does delete-char if there is  a  character  under  the  cursor,
           list-choices  at the end of the line or end-of-file on an empty
           line.  See also those three commands, each of which does only a
           single  action, and delete-char-or-eof, delete-char-or-list and
           list-or-eof, each of which does a  different  two  out  of  the

   down-history (down-arrow, ^N)
           Like up-history, but steps down, stopping at the original input

   end-of-file (not bound)
           Signals an end of file, causing the shell to  exit  unless  the
           ignoreeof  shell  variable  (q.v.) is set to prevent this.  See
           also delete-char-or-list-or-eof.

   expand-history (M-space)
           Expands history substitutions in the current word.  See History
           substitution.  See also magic-space, toggle-literal-history and
           the autoexpand shell variable.

   expand-glob (^X-*)
           Expands the glob-pattern  to  the  left  of  the  cursor.   See
           Filename substitution.

   expand-line (not bound)
           Like  expand-history, but expands history substitutions in each
           word in the input buffer.

   expand-variables (^X-$)
           Expands the variable to the left of the cursor.   See  Variable

   history-search-backward (M-p, M-P)
           Searches  backwards  through  the  history  list  for a command
           beginning with the current contents of the input buffer  up  to
           the  cursor  and  copies  it into the input buffer.  The search
           string  may  be  a  glob-pattern  (see  Filename  substitution)
           containing `*', `?', `[]' or `{}'.  up-history and down-history
           will proceed from the appropriate point in  the  history  list.
           Emacs mode only.  See also history-search-forward and i-search-

   history-search-forward (M-n, M-N)
           Like history-search-backward, but searches forward.

   i-search-back (not bound)
           Searches  backward  like  history-search-backward,  copies  the
           first match into the input buffer with the cursor positioned at
           the end of the pattern, and prompts with `bck: ' and the  first
           match.   Additional  characters  may  be  typed  to  extend the
           search, i-search-back may be typed to continue  searching  with
           the   same   pattern,  wrapping  around  the  history  list  if
           necessary, (i-search-back must be bound to a  single  character
           for  this  to  work) or one of the following special characters
           may be typed:

               ^W      Appends the rest of the word under  the  cursor  to
                       the search pattern.
               delete (or any character bound to backward-delete-char)
                       Undoes  the  effect of the last character typed and
                       deletes a character  from  the  search  pattern  if
               ^G      If  the  previous search was successful, aborts the
                       entire search.  If  not,  goes  back  to  the  last
                       successful search.
               escape  Ends  the  search,  leaving the current line in the
                       input buffer.

           Any other character not bound to self-insert-command terminates
           the  search,  leaving the current line in the input buffer, and
           is then interpreted as normal input.  In particular, a carriage
           return  causes  the  current  line  to be executed.  Emacs mode
           only.  See also i-search-fwd and history-search-backward.

   i-search-fwd (not bound)
           Like i-search-back, but searches forward.

   insert-last-word (M-_)
           Inserts the last word of the previous input  line  (`!$')  into
           the input buffer.  See also copy-prev-word.

   list-choices (M-^D)
           Lists  completion  possibilities  as described under Completion
           and listing.  See  also  delete-char-or-list-or-eof  and  list-

   list-choices-raw (^X-^D)
           Like list-choices, but ignores user-defined completions.

   list-glob (^X-g, ^X-G)
           Lists  (via  the ls-F builtin) matches to the glob-pattern (see
           Filename substitution) to the left of the cursor.

   list-or-eof (not bound)
           Does list-choices or end-of-file on an empty  line.   See  also

   magic-space (not bound)
           Expands history substitutions in the current line, like expand-
           history, and inserts a space.  magic-space is  designed  to  be
           bound to the space bar, but is not bound by default.

   normalize-command (^X-?)
           Searches  for  the  current  word  in PATH and, if it is found,
           replaces it with the full  path  to  the  executable.   Special
           characters  are  quoted.   Aliases  are expanded and quoted but
           commands within aliases are not.  This command is  useful  with
           commands  that  take commands as arguments, e.g., `dbx' and `sh

   normalize-path (^X-n, ^X-N)
           Expands the  current  word  as  described  under  the  `expand'
           setting of the symlinks shell variable.

   overwrite-mode (unbound)
           Toggles between input and overwrite modes.

   run-fg-editor (M-^Z)
           Saves the current input line and looks for a stopped job with a
           name equal to the last component of the file name part  of  the
           EDITOR  or VISUAL environment variables, or, if neither is set,
           `ed' or `vi'.  If such a job is found, it is  restarted  as  if
           `fg  %job'  had  been  typed.   This is used to toggle back and
           forth between an editor and the shell easily.  Some people bind
           this command to `^Z' so they can do this even more easily.

   run-help (M-h, M-H)
           Searches  for  documentation  on the current command, using the
           same notion of `current command' as  the  completion  routines,
           and  prints  it.   There  is no way to use a pager; run-help is
           designed  for  short  help  files.   If   the   special   alias
           helpcommand  is  defined,  it is run with the command name as a
           sole argument.  Else, documentation should be in a  file  named
 , command.1, command.6, command.8 or command, which
           should be in  one  of  the  directories  listed  in  the  HPATH
           environment variable.  If there is more than one help file only
           the first is printed.

   self-insert-command (text characters)
           In insert mode (the default), inserts the typed character  into
           the  input  line  after  the  character  under  the cursor.  In
           overwrite mode, replaces the character under  the  cursor  with
           the  typed  character.   The  input  mode is normally preserved
           between lines, but the inputmode shell variable can be  set  to
           `insert'  or  `overwrite' to put the editor in that mode at the
           beginning of each line.  See also overwrite-mode.

   sequence-lead-in (arrow prefix, meta prefix, ^X)
           Indicates that the following characters are part of a multi-key
           sequence.   Binding  a  command  to a multi-key sequence really
           creates two bindings: the first character  to  sequence-lead-in
           and the whole sequence to the command.  All sequences beginning
           with a character  bound  to  sequence-lead-in  are  effectively
           bound to undefined-key unless bound to another command.

   spell-line (M-$)
           Attempts  to  correct  the  spelling  of each word in the input
           buffer,  like  spell-word,  but  ignores  words   whose   first
           character is one of `-', `!', `^' or `%', or which contain `\',
           `*' or `?', to avoid problems with switches, substitutions  and
           the like.  See Spelling correction.

   spell-word (M-s, M-S)
           Attempts  to  correct  the  spelling  of  the  current  word as
           described under Spelling correction.  Checks each component  of
           a word which appears to be a pathname.

   toggle-literal-history (M-r, M-R)
           Expands  or  `unexpands'  history  substitutions  in  the input
           buffer.  See  also  expand-history  and  the  autoexpand  shell

   undefined-key (any unbound key)

   up-history (up-arrow, ^P)
           Copies  the  previous  entry in the history list into the input
           buffer.  If histlit is set, uses the literal form of the entry.
           May  be  repeated to step up through the history list, stopping
           at the top.

   vi-search-back (?)
           Prompts with `?' for a search string  (which  may  be  a  glob-
           pattern,  as with history-search-backward), searches for it and
           copies it into the input buffer.  The bell rings if no match is
           found.   Hitting  return  ends  the  search and leaves the last
           match in the input buffer.  Hitting escape ends the search  and
           executes the match.  vi mode only.

   vi-search-fwd (/)
           Like vi-search-back, but searches forward.

   which-command (M-?)
           Does  a  which  (see the description of the builtin command) on
           the first word of the input buffer.

   yank-pop (M-y)
           When executed immediately after a  yank  or  another  yank-pop,
           replaces  the  yanked string with the next previous string from
           the  killring.  This  also  has  the  effect  of  rotating  the
           killring,  such  that  this  string will be considered the most
           recently killed by a later  yank  command.  Repeating  yank-pop
           will cycle through the killring any number of times.

   Lexical structure
   The  shell  splits  input  lines  into  words  at blanks and tabs.  The
   special characters `&', `|', `;',  `<',  `>',  `(',  and  `)'  and  the
   doubled characters `&&', `||', `<<' and `>>' are always separate words,
   whether or not they are surrounded by whitespace.

   When the shell's input is not a terminal, the character `#' is taken to
   begin  a  comment.  Each `#' and the rest of the input line on which it
   appears is discarded before further parsing.

   A special character (including a blank or tab) may  be  prevented  from
   having  its special meaning, and possibly made part of another word, by
   preceding it with a backslash (`\') or enclosing it  in  single  (`''),
   double  (`"')  or  backward  (``') quotes.  When not otherwise quoted a
   newline preceded by a `\' is equivalent to a blank, but  inside  quotes
   this sequence results in a newline.

   Furthermore,  all Substitutions (see below) except History substitution
   can be prevented by enclosing the strings  (or  parts  of  strings)  in
   which  they  appear  with  single  quotes  or  by  quoting  the crucial
   character(s) (e.g., `$' or ``' for  Variable  substitution  or  Command
   substitution   respectively)  with  `\'.   (Alias  substitution  is  no
   exception: quoting in any way any character of  a  word  for  which  an
   alias  has  been defined prevents substitution of the alias.  The usual
   way of quoting an alias is to precede it  with  a  backslash.)  History
   substitution  is  prevented  by  backslashes  but not by single quotes.
   Strings  quoted  with  double  or  backward  quotes  undergo   Variable
   substitution  and  Command  substitution,  but  other substitutions are

   Text inside single or double quotes becomes a single word (or  part  of
   one).   Metacharacters  in these strings, including blanks and tabs, do
   not form separate  words.   Only  in  one  special  case  (see  Command
   substitution below) can a double-quoted string yield parts of more than
   one word; single-quoted strings never do.  Backward quotes are special:
   they  signal Command substitution (q.v.), which may result in more than
   one word.

   Quoting complex strings, particularly strings which themselves  contain
   quoting characters, can be confusing.  Remember that quotes need not be
   used as they are in human writing!  It may be easier to  quote  not  an
   entire  string,  but only those parts of the string which need quoting,
   using different types of quoting to do so if appropriate.

   The  backslash_quote  shell  variable  (q.v.)  can  be  set   to   make
   backslashes  always quote `\', `'', and `"'.  (+) This may make complex
   quoting tasks easier, but it can cause syntax errors in csh(1) scripts.

   We now describe the various transformations the shell performs  on  the
   input  in  the  order in which they occur.  We note in passing the data
   structures involved and the commands and variables which  affect  them.
   Remember  that  substitutions  can be prevented by quoting as described
   under Lexical structure.

   History substitution
   Each command, or ``event'', input from the terminal  is  saved  in  the
   history  list.   The  previous command is always saved, and the history
   shell variable can be set to a number to save that many commands.   The
   histdup  shell  variable  can  be  set  to not save duplicate events or
   consecutive duplicate events.

   Saved commands are numbered sequentially from 1 and  stamped  with  the
   time.   It  is  not  usually  necessary  to  use event numbers, but the
   current event number can be made part of the prompt by placing  an  `!'
   in the prompt shell variable.

   The  shell  actually saves history in expanded and literal (unexpanded)
   forms.  If the histlit shell variable is set, commands that display and
   store history use the literal form.

   The  history  builtin  command  can print, store in a file, restore and
   clear the history list at any time, and the savehist and histfile shell
   variables  can be set to store the history list automatically on logout
   and restore it on login.

   History substitutions introduce words from the history  list  into  the
   input  stream, making it easy to repeat commands, repeat arguments of a
   previous command in the current command, or fix  spelling  mistakes  in
   the   previous  command  with  little  typing  and  a  high  degree  of

   History substitutions begin with the character  `!'.   They  may  begin
   anywhere  in  the  input  stream, but they do not nest.  The `!' may be
   preceded by a `\' to prevent its special meaning;  for  convenience,  a
   `!'  is  passed unchanged when it is followed by a blank, tab, newline,
   `=' or `('.  History substitutions also occur when an input line begins
   with  `^'.   This  special  abbreviation  will be described later.  The
   characters used to signal history substitution (`!'  and  `^')  can  be
   changed  by setting the histchars shell variable.  Any input line which
   contains a history substitution is printed before it is executed.

   A history substitution  may  have  an  ``event  specification'',  which
   indicates  the  event  from  which  words  are  to  be  taken, a ``word
   designator'', which selects particular words  from  the  chosen  event,
   and/or a ``modifier'', which manipulates the selected words.

   An event specification can be

       n       A number, referring to a particular event
       -n      An  offset,  referring  to  the  event n before the current
       #       The current  event.   This  should  be  used  carefully  in
               csh(1), where there is no check for recursion.  tcsh allows
               10 levels of recursion.  (+)
       !       The previous event (equivalent to `-1')
       s       The most recent event whose  first  word  begins  with  the
               string s
       ?s?     The  most  recent  event  which contains the string s.  The
               second `?' can be omitted if it is immediately followed  by
               a newline.

   For example, consider this bit of someone's history list:

        9  8:30    nroff -man
       10  8:31    cp
       11  8:36    vi
       12  8:37    diff

   The  commands  are shown with their event numbers and time stamps.  The
   current event, which we haven't typed in yet, is event 13.   `!11'  and
   `!-2'  refer to event 11.  `!!' refers to the previous event, 12.  `!!'
   can be abbreviated `!' if it is  followed  by  `:'  (`:'  is  described
   below).   `!n' refers to event 9, which begins with `n'.  `!?old?' also
   refers to event 12, which contains `old'.  Without word designators  or
   modifiers  history  references simply expand to the entire event, so we
   might type `!cp' to redo the copy command or `!!|more'  if  the  `diff'
   output scrolled off the top of the screen.

   History  references  may  be  insulated  from the surrounding text with
   braces if necessary.  For example, `!vdoc' would  look  for  a  command
   beginning  with  `vdoc',  and,  in  this  example,  not  find  one, but
   `!{v}doc' would expand unambiguously to `vi  wumpus.mandoc'.   Even  in
   braces, history substitutions do not nest.

   (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
   `d' appended to it, tcsh expands it to the last  event  beginning  with
   `3d';  only  completely numeric arguments are treated as event numbers.
   This makes it possible to recall events  beginning  with  numbers.   To
   expand `!3d' as in csh(1) say `!{3}d'.

   To  select words from an event we can follow the event specification by
   a `:' and a designator for the desired words.  The words  of  an  input
   line are numbered from 0, the first (usually command) word being 0, the
   second word (first argument) being 1, etc.  The basic word  designators

       0       The first (command) word
       n       The nth argument
       ^       The first argument, equivalent to `1'
       $       The last argument
       %       The word matched by an ?s? search
       x-y     A range of words
       -y      Equivalent to `0-y'
       *       Equivalent  to  `^-$',  but  returns  nothing  if the event
               contains only 1 word
       x*      Equivalent to `x-$'
       x-      Equivalent to `x*', but omitting the last word (`$')

   Selected words are inserted into the command line separated  by  single
   blanks.   For example, the `diff' command in the previous example might
   have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
   argument  from  the previous event) or `diff !-2:2 !-2:1' to select and
   swap the arguments from the `cp' command.  If we didn't care about  the
   order  of  the `diff' we might have said `diff !-2:1-2' or simply `diff
   !-2:*'.  The `cp'  command  might  have  been  written  `cp
   !#:1.old',  using `#' to refer to the current event.  `!n:-'
   would reuse the first two words from the `nroff' command to say  `nroff

   The `:' separating the event specification from the word designator can
   be omitted if the argument selector begins with a `^', `$', `*', `%' or
   `-'.   For  example,  our  `diff' command might have been `diff !!^.old
   !!^' or,  equivalently,  `diff  !!$.old  !!$'.   However,  if  `!!'  is
   abbreviated  `!',  an  argument  selector  beginning  with  `-' will be
   interpreted as an event specification.

   A  history  reference  may  have  a  word  designator  but   no   event
   specification.   It  then  references the previous command.  Continuing
   our `diff' example, we could have said simply `diff !^.old !^'  or,  to
   get the arguments in the opposite order, just `diff !*'.

   The   word   or  words  in  a  history  reference  can  be  edited,  or
   ``modified'', by following it with one or more modifiers, each preceded
   by a `:':

       h       Remove a trailing pathname component, leaving the head.
       t       Remove all leading pathname components, leaving the tail.
       r       Remove a filename extension `.xxx', leaving the root name.
       e       Remove all but the extension.
       u       Uppercase the first lowercase letter.
       l       Lowercase the first uppercase letter.
       s/l/r/  Substitute  l  for  r.   l is simply a string like r, not a
               regular expression as in the eponymous ed(1) command.   Any
               character  may  be used as the delimiter in place of `/'; a
               `\' can be used to quote the delimiter inside l and r.  The
               character  `&'  in  the r is replaced by l; `\' also quotes
               `&'.   If  l  is  empty  (``''),  the  l  from  a  previous
               substitution  or  the  s  from  a  previous search or event
               number  in  event  specification  is  used.   The  trailing
               delimiter may be omitted if it is immediately followed by a
       &       Repeat the previous substitution.
       g       Apply the following modifier once to each word.
       a (+)   Apply the following modifier as many times as possible to a
               single  word.   `a' and `g' can be used together to apply a
               modifier  globally.   With  the  `s'  modifier,  only   the
               patterns  contained  in  the original word are substituted,
               not patterns that contain any substitution result.
       p       Print the new command line but do not execute it.
       q       Quote   the   substituted   words,    preventing    further
       x       Like q, but break into words at blanks, tabs and newlines.

   Modifiers  are applied to only the first modifiable word (unless `g' is
   used).  It is an error for no word to be modifiable.

   For example, the `diff'  command  might  have  been  written  as  `diff  !#^:r',  using  `:r'  to  remove  `.old' from the first
   argument on the same line  (`!#^').   We  could  say  `echo  hello  out
   there',  then `echo !*:u' to capitalize `hello', `echo !*:au' to say it
   out loud, or `echo !*:agu' to really shout.  We might follow  `mail  -s
   "I forgot my password" rot' with `!:s/rot/root' to correct the spelling
   of `root' (but see Spelling correction for a different approach).

   There is a special abbreviation for substitutions.  `^', when it is the
   first  character  on  an  input line, is equivalent to `!:s^'.  Thus we
   might have said `^rot^root' to make  the  spelling  correction  in  the
   previous example.  This is the only history substitution which does not
   explicitly begin with `!'.

   (+) In csh as such, only one modifier may be applied to each history or
   variable expansion.  In tcsh, more than one may be used, for example

       % mv /usr/man/man1/wumpus.1
       % man !$:t:r
       man wumpus

   In csh, the result would be `wumpus.1:r'.  A substitution followed by a
   colon may need to be insulated from it with braces:

       > mv a.out /usr/games/wumpus
       > setenv PATH !$:h:$PATH
       Bad ! modifier: $.
       > setenv PATH !{-2$:h}:$PATH
       setenv PATH /usr/games:/bin:/usr/bin:.

   The first attempt would succeed in csh but fails in tcsh, because  tcsh
   expects another modifier after the second colon rather than `$'.

   Finally,  history can be accessed through the editor as well as through
   the substitutions just described.  The up- and  down-history,  history-
   search-backward  and  -forward,  i-search-back and -fwd, vi-search-back
   and -fwd, copy-prev-word and insert-last-word  editor  commands  search
   for  events  in  the  history list and copy them into the input buffer.
   The toggle-literal-history editor command switches between the expanded
   and literal forms of history lines in the input buffer.  expand-history
   and expand-line expand history substitutions in the current word and in
   the entire input buffer respectively.

   Alias substitution
   The  shell  maintains  a  list  of  aliases which can be set, unset and
   printed by the alias and unalias commands.  After  a  command  line  is
   parsed  into  simple  commands  (see  Commands)  the first word of each
   command, left-to-right, is checked to see if it has an alias.   If  so,
   the  first  word  is  replaced  by  the alias.  If the alias contains a
   history reference, it undergoes History substitution (q.v.)  as  though
   the  original  command were the previous input line.  If the alias does
   not contain a history reference, the argument list is left untouched.

   Thus if the alias for `ls' were `ls -l' the  command  `ls  /usr'  would
   become  `ls -l /usr', the argument list here being undisturbed.  If the
   alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill'  would
   become  `grep  bill  /etc/passwd'.   Aliases  can  be used to introduce
   parser metasyntax.  For example, `alias print 'pr \!* | lpr'' defines a
   ``command'' (`print') which pr(1)s its arguments to the line printer.

   Alias  substitution is repeated until the first word of the command has
   no alias.  If an alias substitution does not change the first word  (as
   in  the previous example) it is flagged to prevent a loop.  Other loops
   are detected and cause an error.

   Some aliases are referred to by the shell; see Special aliases.

   Variable substitution
   The shell maintains a list of variables, each of which has as  value  a
   list  of  zero  or  more  words.   The values of shell variables can be
   displayed and changed with the set  and  unset  commands.   The  system
   maintains  its  own  list  of  ``environment'' variables.  These can be
   displayed and changed with printenv, setenv and unsetenv.

   (+) Variables may be made read-only with `set  -r'  (q.v.).   Read-only
   variables  may not be modified or unset; attempting to do so will cause
   an error.  Once made read-only, a variable cannot be made writable,  so
   `set  -r' should be used with caution.  Environment variables cannot be
   made read-only.

   Some variables are set  by  the  shell  or  referred  to  by  it.   For
   instance,  the  argv variable is an image of the shell's argument list,
   and words of this variable's value are referred  to  in  special  ways.
   Some  of  the variables referred to by the shell are toggles; the shell
   does not care what their value is, only whether they are  set  or  not.
   For  instance,  the  verbose  variable is a toggle which causes command
   input to be echoed.  The -v command line  option  sets  this  variable.
   Special  shell  variables  lists all variables which are referred to by
   the shell.

   Other operations treat variables numerically.  The `@' command  permits
   numeric  calculations  to  be  performed  and  the result assigned to a
   variable.  Variable values are, however, always represented as (zero or
   more) strings.  For the purposes of numeric operations, the null string
   is considered to be zero, and the second and subsequent words of multi-
   word values are ignored.

   After  the input line is aliased and parsed, and before each command is
   executed, variable substitution is performed keyed by  `$'  characters.
   This  expansion can be prevented by preceding the `$' with a `\' except
   within `"'s where it always occurs, and  within  `''s  where  it  never
   occurs.   Strings  quoted  by  ``'  are  interpreted later (see Command
   substitution below) so `$' substitution  does  not  occur  there  until
   later,  if  at  all.  A `$' is passed unchanged if followed by a blank,
   tab, or end-of-line.

   Input/output redirections are recognized before variable expansion, and
   are  variable  expanded  separately.   Otherwise,  the command name and
   entire argument list are expanded together.  It is  thus  possible  for
   the  first  (command)  word  (to  this point) to generate more than one
   word, the first of which becomes the command  name,  and  the  rest  of
   which become arguments.

   Unless  enclosed  in  `"'  or  given  the  `:q' modifier the results of
   variable  substitution  may  eventually   be   command   and   filename
   substituted.   Within  `"', a variable whose value consists of multiple
   words expands to a (portion of a) single word, with the  words  of  the
   variable's  value  separated  by  blanks.   When  the  `:q' modifier is
   applied to a substitution the variable will expand  to  multiple  words
   with each word separated by a blank and quoted to prevent later command
   or filename substitution.

   The following  metasequences  are  provided  for  introducing  variable
   values  into  the  shell  input.   Except  as  noted, it is an error to
   reference a variable which is not set.

   ${name} Substitutes the words of  the  value  of  variable  name,  each
           separated  by  a  blank.   Braces  insulate name from following
           characters  which  would  otherwise  be  part  of  it.    Shell
           variables  have names consisting of letters and digits starting
           with a  letter.   The  underscore  character  is  considered  a
           letter.   If  name  is  not a shell variable, but is set in the
           environment, then that value is returned (but some of the other
           forms given below are not available in this case).
           Substitutes  only  the  selected  words from the value of name.
           The selector is subjected to `$' substitution and  may  consist
           of  a  single  number  or  two numbers separated by a `-'.  The
           first word of a variable's value is numbered `1'.  If the first
           number  of  a range is omitted it defaults to `1'.  If the last
           member of a range is omitted  it  defaults  to  `$#name'.   The
           selector `*' selects all words.  It is not an error for a range
           to be empty if the second argument is omitted or in range.
   $0      Substitutes the name of the file from which  command  input  is
           being read.  An error occurs if the name is not known.
           Equivalent to `$argv[number]'.
   $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

   The  `:'  modifiers  described  under  History substitution, except for
   `:p', can be applied to the substitutions above.  More than one may  be
   used.   (+)  Braces  may  be needed to insulate a variable substitution
   from a literal colon just as  with  History  substitution  (q.v.);  any
   modifiers must appear within the braces.

   The following substitutions can not be modified with `:' modifiers.

           Substitutes the string `1' if name is set, `0' if it is not.
   $?0     Substitutes  `1' if the current input filename is known, `0' if
           it is not.  Always `0' in interactive shells.
           Substitutes the number of words in name.
   $#      Equivalent to `$#argv'.  (+)
           Substitutes the number of characters in name.  (+)
           Substitutes the number of characters in $argv[number].  (+)
   $?      Equivalent to `$status'.  (+)
   $$      Substitutes the (decimal) process number of the (parent) shell.
   $!      Substitutes the (decimal) process number of the last background
           process started by this shell.  (+)
   $_      Substitutes the command line of the last command executed.  (+)
   $<      Substitutes  a  line  from  the standard input, with no further
           interpretation thereafter.  It can be used  to  read  from  the
           keyboard in a shell script.  (+) While csh always quotes $<, as
           if it were equivalent to `$<:q', tcsh does  not.   Furthermore,
           when  tcsh  is waiting for a line to be typed the user may type
           an interrupt to interrupt the sequence into which the  line  is
           to be substituted, but csh does not allow this.

   The  editor  command expand-variables, normally bound to `^X-$', can be
   used to interactively expand individual variables.

   Command, filename and directory stack substitution
   The remaining substitutions are applied selectively to the arguments of
   builtin  commands.   This  means that portions of expressions which are
   not evaluated are not subjected  to  these  expansions.   For  commands
   which  are  not  internal to the shell, the command name is substituted
   separately from the argument list.  This occurs very late, after input-
   output redirection is performed, and in a child of the main shell.

   Command substitution
   Command  substitution  is  indicated by a command enclosed in ``'.  The
   output from such a command is broken into  separate  words  at  blanks,
   tabs  and  newlines,  and  null  words  are  discarded.   The output is
   variable and command substituted and  put  in  place  of  the  original

   Command  substitutions  inside  double  quotes  (`"') retain blanks and
   tabs; only newlines force new words.  The single final newline does not
   force  a  new  word  in  any  case.   It is thus possible for a command
   substitution to yield only part of a word, even if the command  outputs
   a complete line.

   By  default,  the  shell  since  version  6.12 replaces all newline and
   carriage return characters in  the  command  by  spaces.   If  this  is
   switched  off  by  unsetting  csubstnonl, newlines separate commands as

   Filename substitution
   If a word contains any of the characters `*', `?', `[' or `{' or begins
   with  the  character  `~'  it is a candidate for filename substitution,
   also known as ``globbing''.  This word is then regarded  as  a  pattern
   (``glob-pattern''),  and replaced with an alphabetically sorted list of
   file names which match the pattern.

   In matching filenames, the character `.' at the beginning of a filename
   or  immediately  following  a `/', as well as the character `/' must be
   matched explicitly (unless either  globdot  or  globstar  or  both  are
   set(+)).  The character `*' matches any string of characters, including
   the null string.  The character `?' matches any single character.   The
   sequence  `[...]'  matches  any one of the characters enclosed.  Within
   `[...]', a pair of characters separated by `-'  matches  any  character
   lexically between the two.

   (+)  Some  glob-patterns  can be negated: The sequence `[^...]' matches
   any single character not specified by the characters and/or  ranges  of
   characters in the braces.

   An entire glob-pattern can also be negated with `^':

       > echo *
       bang crash crunch ouch
       > echo ^cr*
       bang ouch

   Glob-patterns  which  do not use `?', `*', or `[]' or which use `{}' or
   `~' (below) are not negated correctly.

   The metanotation `a{b,c,d}e' is a shorthand for `abe ace  ade'.   Left-
   to-right  order  is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
   `/usr/source/s1/oldls.c /usr/source/s1/ls.c'.  The results  of  matches
   are   sorted  separately  at  a  low  level  to  preserve  this  order:
   `../{memo,*box}' might expand to `../memo ../box ../mbox'.  (Note  that
   `memo'  was not sorted with the results of matching `*box'.)  It is not
   an error when this construct expands to files which do not  exist,  but
   it  is  possible  to  get an error from a command to which the expanded
   list is passed.  This construct may be nested.  As a special  case  the
   words `{', `}' and `{}' are passed undisturbed.

   The  character  `~'  at  the  beginning  of  a  filename refers to home
   directories.  Standing alone, i.e., `~', it expands  to  the  invoker's
   home  directory  as  reflected in the value of the home shell variable.
   When  followed  by  a  name  consisting  of  letters,  digits  and  `-'
   characters the shell searches for a user with that name and substitutes
   their home directory;  thus  `~ken'  might  expand  to  `/usr/ken'  and
   `~ken/chmach'  to  `/usr/ken/chmach'.  If the character `~' is followed
   by a character other than a letter or `/' or appears elsewhere than  at
   the  beginning  of  a  word,  it  is  left undisturbed.  A command like
   `setenv MANPATH /usr/man:/usr/local/man:~/lib/man' does not, therefore,
   do home directory substitution as one might hope.

   It is an error for a glob-pattern containing `*', `?', `[' or `~', with
   or without `^', not to match any files.  However, only one pattern in a
   list  of  glob-patterns  must  match a file (so that, e.g., `rm *.a *.c
   *.o' would fail only if there were no files in  the  current  directory
   ending  in `.a', `.c', or `.o'), and if the nonomatch shell variable is
   set a pattern (or list of  patterns)  which  matches  nothing  is  left
   unchanged rather than causing an error.

   The globstar shell variable can be set to allow `**' or `***' as a file
   glob pattern that matches  any  string  of  characters  including  `/',
   recursively  traversing any existing sub-directories.  For example, `ls
   **.c' will list all the .c files in the  current  directory  tree.   If
   used  by itself, it will match match zero or more sub-directories (e.g.
   `ls /usr/include/**/time.h' will list any file named  `time.h'  in  the
   /usr/include  directory tree; `ls /usr/include/**time.h' will match any
   file in the /usr/include directory tree ending  in  `time.h';  and  `ls
   /usr/include/**time**.h' will match any .h file with `time' either in a
   subdirectory name or in the filename itself).  To prevent problems with
   recursion,  the `**' glob-pattern will not descend into a symbolic link
   containing a directory.  To override this, use `***' (+)

   The noglob shell variable can be set to prevent filename  substitution,
   and  the  expand-glob  editor command, normally bound to `^X-*', can be
   used to interactively expand individual filename substitutions.

   Directory stack substitution (+)
   The directory stack is a list of directories, numbered from zero,  used
   by  the  pushd, popd and dirs builtin commands (q.v.).  dirs can print,
   store in a file, restore and clear the directory stack at any time, and
   the  savedirs  and  dirsfile  shell  variables  can be set to store the
   directory stack automatically on logout and restore it on  login.   The
   dirstack  shell variable can be examined to see the directory stack and
   set to put arbitrary directories into the directory stack.

   The character `=' followed by one or more digits expands to an entry in
   the  directory  stack.   The  special  case  `=-'  expands  to the last
   directory in the stack.  For example,

       > dirs -v
       0       /usr/bin
       1       /usr/spool/uucp
       2       /usr/accts/sys
       > echo =1
       > echo =0/calendar
       > echo =-

   The noglob and nonomatch shell variables  and  the  expand-glob  editor
   command apply to directory stack as well as filename substitutions.

   Other substitutions (+)
   There   are  several  more  transformations  involving  filenames,  not
   strictly related to the above but mentioned here for completeness.  Any
   filename  may  be  expanded  to  a full path when the symlinks variable
   (q.v.) is set to `expand'.  Quoting prevents this  expansion,  and  the
   normalize-path editor command does it on demand.  The normalize-command
   editor command expands commands in PATH  into  full  paths  on  demand.
   Finally,  cd  and  pushd  interpret  `-'  as  the old working directory
   (equivalent to the shell variable owd).  This is not a substitution  at
   all,   but   an   abbreviation   recognized  by  only  those  commands.
   Nonetheless, it too can be prevented by quoting.

   The next three sections describe how the shell  executes  commands  and
   deals with their input and output.

   Simple commands, pipelines and sequences
   A  simple  command is a sequence of words, the first of which specifies
   the command to be executed.  A series of simple commands joined by  `|'
   characters  forms a pipeline.  The output of each command in a pipeline
   is connected to the input of the next.

   Simple commands and pipelines may be joined into  sequences  with  `;',
   and  will be executed sequentially.  Commands and pipelines can also be
   joined into sequences with `||'  or  `&&',  indicating,  as  in  the  C
   language,  that the second is to be executed only if the first fails or
   succeeds respectively.

   A simple command, pipeline or sequence may be  placed  in  parentheses,
   `()',  to  form a simple command, which may in turn be a component of a
   pipeline or sequence.  A command, pipeline or sequence can be  executed
   without waiting for it to terminate by following it with an `&'.

   Builtin and non-builtin command execution
   Builtin  commands are executed within the shell.  If any component of a
   pipeline except the last is a builtin command, the pipeline is executed
   in a subshell.

   Parenthesized commands are always executed in a subshell.

       (cd; pwd); pwd

   thus  prints  the  home directory, leaving you where you were (printing
   this after the home directory), while

       cd; pwd

   leaves you in the home  directory.   Parenthesized  commands  are  most
   often used to prevent cd from affecting the current shell.

   When  a command to be executed is found not to be a builtin command the
   shell attempts to execute the command via execve(2).  Each word in  the
   variable  path  names  a directory in which the shell will look for the
   command.  If the shell is not given a -f option, the shell  hashes  the
   names  in  these directories into an internal table so that it will try
   an execve(2) in only a directory where there is a possibility that  the
   command  resides  there.   This  greatly speeds command location when a
   large number of directories  are  present  in  the  search  path.  This
   hashing mechanism is not used:

   1.  If hashing is turned explicitly off via unhash.

   2.  If the shell was given a -f argument.

   3.  For  each  directory  component of path which does not begin with a

   4.  If the command contains a `/'.

   In the above four cases the shell concatenates each  component  of  the
   path  vector  with the given command name to form a path name of a file
   which it then attempts to execute it. If execution is  successful,  the
   search stops.

   If  the  file  has  execute permissions but is not an executable to the
   system (i.e., it is neither an executable  binary  nor  a  script  that
   specifies  its interpreter), then it is assumed to be a file containing
   shell commands and a new shell  is  spawned  to  read  it.   The  shell
   special alias may be set to specify an interpreter other than the shell

   On  systems  which  do  not  understand  the  `#!'  script  interpreter
   convention  the  shell  may  be compiled to emulate it; see the version
   shell variable.  If so, the shell checks the first line of the file  to
   see  if it is of the form `#!interpreter arg ...'.  If it is, the shell
   starts interpreter with the given args and feeds  the  file  to  it  on
   standard input.

   The  standard  input and standard output of a command may be redirected
   with the following syntax:

   < name  Open file name (which is first variable, command  and  filename
           expanded) as the standard input.
   << word Read  the  shell input up to a line which is identical to word.
           word  is  not  subjected  to  variable,  filename  or   command
           substitution,  and  each  input line is compared to word before
           any substitutions are  done  on  this  input  line.   Unless  a
           quoting  `\',  `"',  `'  or  ``'  appears  in word variable and
           command substitution is performed  on  the  intervening  lines,
           allowing  `\'  to  quote  `$', `\' and ``'.  Commands which are
           substituted have all  blanks,  tabs,  and  newlines  preserved,
           except  for  the final newline which is dropped.  The resultant
           text is placed in an anonymous temporary file which is given to
           the command as standard input.
   > name
   >! name
   >& name
   >&! name
           The file name is used as standard output.  If the file does not
           exist then it is created; if the file exists, it is  truncated,
           its previous contents being lost.

           If  the shell variable noclobber is set, then the file must not
           exist or be a character  special  file  (e.g.,  a  terminal  or
           `/dev/null')   or   an   error  results.   This  helps  prevent
           accidental destruction of files.  In this case  the  `!'  forms
           can be used to suppress this check.

           The  forms  involving  `&' route the diagnostic output into the
           specified file  as  well  as  the  standard  output.   name  is
           expanded in the same way as `<' input filenames are.
   >> name
   >>& name
   >>! name
   >>&! name
           Like  `>', but appends output to the end of name.  If the shell
           variable noclobber is set, then it is an error for the file not
           to exist, unless one of the `!' forms is given.

   A  command  receives  the environment in which the shell was invoked as
   modified by the input-output parameters and the presence of the command
   in  a pipeline.  Thus, unlike some previous shells, commands run from a
   file of shell commands have no access to the text of  the  commands  by
   default;  rather they receive the original standard input of the shell.
   The `<<' mechanism should be used to present inline data.  This permits
   shell command scripts to function as components of pipelines and allows
   the shell to block read its input.   Note  that  the  default  standard
   input  for  a command run detached is not the empty file /dev/null, but
   the original standard input of the shell.  If this is a terminal and if
   the  process  attempts to read from the terminal, then the process will
   block and the user will be notified (see Jobs).

   Diagnostic output may be directed through  a  pipe  with  the  standard
   output.  Simply use the form `|&' rather than just `|'.

   The  shell  cannot  presently  redirect  diagnostic output without also
   redirecting standard output, but `(command  >  output-file)  >&  error-
   file'  is often an acceptable workaround.  Either output-file or error-
   file may be `/dev/tty' to send output to the terminal.

   Having described how the shell accepts,  parses  and  executes  command
   lines, we now turn to a variety of its useful features.

   Control flow
   The  shell  contains a number of commands which can be used to regulate
   the flow of control in command files (shell scripts)  and  (in  limited
   but  useful  ways)  from terminal input.  These commands all operate by
   forcing the shell to reread or skip  in  its  input  and,  due  to  the
   implementation, restrict the placement of some of the commands.

   The  foreach, switch, and while statements, as well as the if-then-else
   form of the if statement, require that the major keywords appear  in  a
   single simple command on an input line as shown below.

   If  the  shell's  input  is  not  seekable,  the shell buffers up input
   whenever a loop is being read  and  performs  seeks  in  this  internal
   buffer to accomplish the rereading implied by the loop.  (To the extent
   that this allows, backward gotos will succeed on non-seekable inputs.)

   The if, while and exit builtin commands use expressions with  a  common
   syntax.   The expressions can include any of the operators described in
   the next three sections.  Note that the @ builtin  command  (q.v.)  has
   its own separate syntax.

   Logical, arithmetical and comparison operators
   These operators are similar to those of C and have the same precedence.
   They include

       ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
       <  > <<  >>  +  -  *  /  %  !  ~  (  )

   Here the precedence increases to the right, `==' `!='  `=~'  and  `!~',
   `<='  `>='  `<'  and  `>',  `<<' and `>>', `+' and `-', `*' `/' and `%'
   being, in groups, at the same level.   The  `=='  `!='  `=~'  and  `!~'
   operators  compare  their  arguments  as strings; all others operate on
   numbers.  The operators `=~' and `!~' are like  `!='  and  `=='  except
   that  the right hand side is a glob-pattern (see Filename substitution)
   against which the left hand operand is matched.  This reduces the  need
   for use of the switch builtin command in shell scripts when all that is
   really needed is pattern matching.

   Null or missing arguments are  considered  `0'.   The  results  of  all
   expressions  are  strings,  which  represent  decimal  numbers.   It is
   important to note that no two components of an expression can appear in
   the  same word; except when adjacent to components of expressions which
   are syntactically significant to the parser (`&' `|' `<' `>'  `('  `)')
   they should be surrounded by spaces.

   Command exit status
   Commands  can be executed in expressions and their exit status returned
   by enclosing them in braces (`{}').  Remember that the braces should be
   separated  from the words of the command by spaces.  Command executions
   succeed, returning true, i.e., `1', if the command exits with status 0,
   otherwise  they  fail,  returning  false,  i.e., `0'.  If more detailed
   status information is required then  the  command  should  be  executed
   outside of an expression and the status shell variable examined.

   File inquiry operators
   Some  of  these operators perform true/false tests on files and related
   objects.  They are of the form -op file, where op is one of

       r   Read access
       w   Write access
       x   Execute access
       X   Executable in the path or shell builtin, e.g., `-X ls' and  `-X
           ls-F' are generally true, but `-X /bin/ls' is not (+)
       e   Existence
       o   Ownership
       z   Zero size
       s   Non-zero size (+)
       f   Plain file
       d   Directory
       l   Symbolic link (+) *
       b   Block special file (+)
       c   Character special file (+)
       p   Named pipe (fifo) (+) *
       S   Socket special file (+) *
       u   Set-user-ID bit is set (+)
       g   Set-group-ID bit is set (+)
       k   Sticky bit is set (+)
       t   file  (which  must be a digit) is an open file descriptor for a
           terminal device (+)
       R   Has been migrated (Convex only) (+)
       L   Applies subsequent operators in a multiple-operator test  to  a
           symbolic  link rather than to the file to which the link points
           (+) *

   file is command and filename expanded and then tested to see if it  has
   the specified relationship to the real user.  If file does not exist or
   is inaccessible  or,  for  the  operators  indicated  by  `*',  if  the
   specified  file  type  does  not  exist on the current system, then all
   enquiries return false, i.e., `0'.

   These  operators  may  be  combined  for  conciseness:  `-xy  file'  is
   equivalent  to  `-x  file  && -y file'.  (+) For example, `-fx' is true
   (returns `1') for plain executable files, but not for directories.

   L may be used in a multiple-operator test to apply subsequent operators
   to  a  symbolic  link rather than to the file to which the link points.
   For example, `-lLo' is true for links owned by the invoking user.   Lr,
   Lw  and  Lx are always true for links and false for non-links.  L has a
   different meaning when it is the last operator in  a  multiple-operator
   test; see below.

   It  is  possible  but  not useful, and sometimes misleading, to combine
   operators which expect file to be a file with operators  which  do  not
   (e.g.,  X  and  t).   Following  L with a non-file operator can lead to
   particularly strange results.

   Other operators return other information, i.e., not just  `0'  or  `1'.
   (+) They have the same format as before; op may be one of

       A       Last  file  access time, as the number of seconds since the
       A:      Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
       M       Last file modification time
       M:      Like M, but in timestamp format
       C       Last inode modification time
       C:      Like C, but in timestamp format
       D       Device number
       I       Inode number
       F       Composite file identifier, in the form device:inode
       L       The name of the file pointed to by a symbolic link
       N       Number of (hard) links
       P       Permissions, in octal, without leading zero
       P:      Like P, with leading zero
       Pmode   Equivalent  to  `-P file & mode', e.g., `-P22 file' returns
               `22' if file is writable by group and  other,  `20'  if  by
               group only, and `0' if by neither
       Pmode:  Like Pmode, with leading zero
       U       Numeric userid
       U:      Username, or the numeric userid if the username is unknown
       G       Numeric groupid
       G:      Groupname,  or  the  numeric  groupid  if  the groupname is
       Z       Size, in bytes

   Only one of these operators may appear in a multiple-operator test, and
   it must be the last.  Note that L has a different meaning at the end of
   and elsewhere in a multiple-operator test.   Because  `0'  is  a  valid
   return  value  for many of these operators, they do not return `0' when
   they fail: most return `-1', and F returns `:'.

   If the shell is compiled with POSIX  defined  (see  the  version  shell
   variable), the result of a file inquiry is based on the permission bits
   of the file and not on the result of the access(2)  system  call.   For
   example, if one tests a file with -w whose permissions would ordinarily
   allow writing but which is on a file system mounted read-only, the test
   will succeed in a POSIX shell but fail in a non-POSIX shell.

   File  inquiry operators can also be evaluated with the filetest builtin
   command (q.v.) (+).

   The shell associates a job with each pipeline.  It  keeps  a  table  of
   current  jobs,  printed  by  the  jobs  command, and assigns them small
   integer numbers.  When a job is started asynchronously  with  `&',  the
   shell prints a line which looks like

       [1] 1234

   indicating that the job which was started asynchronously was job number
   1 and had one (top-level) process, whose process id was 1234.

   If you are running a job and wish to do something else you may hit  the
   suspend  key  (usually  `^Z'), which sends a STOP signal to the current
   job.  The shell will then normally  indicate  that  the  job  has  been
   `Suspended'  and  print another prompt.  If the listjobs shell variable
   is set, all jobs will be listed like the jobs builtin command; if it is
   set  to `long' the listing will be in long format, like `jobs -l'.  You
   can then manipulate the state of the suspended job.  You can put it  in
   the  ``background''  with the bg command or run some other commands and
   eventually bring the job back into the ``foreground''  with  fg.   (See
   also   the   run-fg-editor   editor  command.)   A  `^Z'  takes  effect
   immediately and is like an interrupt in that pending output and  unread
   input  are discarded when it is typed.  The wait builtin command causes
   the shell to wait for all background jobs to complete.

   The `^]' key sends a delayed suspend signal, which does not generate  a
   STOP signal until a program attempts to read(2) it, to the current job.
   This can usefully be typed ahead when you have prepared  some  commands
   for  a job which you wish to stop after it has read them.  The `^Y' key
   performs this function in csh(1); in tcsh, `^Y' is an editing  command.

   A  job  being  run in the background stops if it tries to read from the
   terminal.  Background jobs are normally allowed to produce output,  but
   this  can  be disabled by giving the command `stty tostop'.  If you set
   this tty option, then background  jobs  will  stop  when  they  try  to
   produce output like they do when they try to read input.

   There  are  several  ways to refer to jobs in the shell.  The character
   `%' introduces a job name.  If you wish to refer to job number  1,  you
   can  name  it  as `%1'.  Just naming a job brings it to the foreground;
   thus `%1' is a synonym for `fg  %1',  bringing  job  1  back  into  the
   foreground.   Similarly, saying `%1 &' resumes job 1 in the background,
   just like `bg %1'.  A job can also be named by an unambiguous prefix of
   the  string  typed  in  to  start  it:  `%ex'  would normally restart a
   suspended ex(1) job, if there were only one suspended  job  whose  name
   began  with  the string `ex'.  It is also possible to say `%?string' to
   specify a job whose text contains string, if there  is  only  one  such

   The  shell  maintains  a  notion  of the current and previous jobs.  In
   output pertaining to jobs, the current job is marked with a `+' and the
   previous  job with a `-'.  The abbreviations `%+', `%', and (by analogy
   with the syntax of the history mechanism) `%%' all refer to the current
   job, and `%-' refers to the previous job.

   The job control mechanism requires that the stty(1) option `new' be set
   on some systems.  It is an artifact from a `new' implementation of  the
   tty  driver  which  allows  generation of interrupt characters from the
   keyboard to tell jobs to stop.   See  stty(1)  and  the  setty  builtin
   command for details on setting options in the new tty driver.

   Status reporting
   The  shell  learns  immediately  whenever  a process changes state.  It
   normally informs you whenever a job becomes blocked so that no  further
   progress  is  possible, but only right before it prints a prompt.  This
   is done so that it does not otherwise disturb your work.  If,  however,
   you   set  the  shell  variable  notify,  the  shell  will  notify  you
   immediately of changes of status in background jobs.  There is  also  a
   shell  command  notify  which marks a single process so that its status
   changes will be immediately reported.   By  default  notify  marks  the
   current process; simply say `notify' after starting a background job to
   mark it.

   When you try to leave the shell while jobs are  stopped,  you  will  be
   warned that `There are suspended jobs.' You may use the jobs command to
   see what they are.  If you do this or immediately try  to  exit  again,
   the  shell will not warn you a second time, and the suspended jobs will
   be terminated.

   Automatic, periodic and timed events (+)
   There  are  various  ways  to  run  commands  and  take  other  actions
   automatically  at  various  times  in  the ``life cycle'' of the shell.
   They are summarized here, and described in detail under the appropriate
   Builtin commands, Special shell variables and Special aliases.

   The  sched  builtin command puts commands in a scheduled-event list, to
   be executed by the shell at a given time.

   The beepcmd, cwdcmd, periodic,  precmd,  postcmd,  and  jobcmd  Special
   aliases  can  be  set, respectively, to execute commands when the shell
   wants to ring the bell,  when  the  working  directory  changes,  every
   tperiod minutes, before each prompt, before each command gets executed,
   after each command gets executed, and when  a  job  is  started  or  is
   brought into the foreground.

   The  autologout  shell variable can be set to log out or lock the shell
   after a given number of minutes of inactivity.

   The mail shell variable can be set to check for new mail periodically.

   The printexitvalue shell variable can be set to print the  exit  status
   of commands which exit with a status other than zero.

   The  rmstar  shell  variable can be set to ask the user, when `rm *' is
   typed, if that is really what was meant.

   The time shell variable can be set to execute the time builtin  command
   after the completion of any process that takes more than a given number
   of CPU seconds.

   The watch and who shell variables can be set to  report  when  selected
   users log in or out, and the log builtin command reports on those users
   at any time.

   Native Language System support (+)
   The shell is eight bit clean (if so compiled;  see  the  version  shell
   variable)  and  thus  supports  character sets needing this capability.
   NLS support differs depending on whether or not the shell was  compiled
   to  use  the  system's NLS (again, see version).  In either case, 7-bit
   ASCII is the default character code (e.g., the classification of  which
   characters  are  printable)  and  sorting,  and  changing  the  LANG or
   LC_CTYPE environment variables causes a check for possible  changes  in
   these respects.

   When  using  the  system's  NLS, the setlocale(3) function is called to
   determine appropriate character code/classification and sorting  (e.g.,
   a  'en_CA.UTF-8'  would  yield  "UTF-8"  as  a  character  code).  This
   function  typically  examines  the  LANG   and   LC_CTYPE   environment
   variables; refer to the system documentation for further details.  When
   not using the system's NLS, the shell simulates it by assuming that the
   ISO  8859-1  character  set  is  used  whenever  either of the LANG and
   LC_CTYPE variables are set, regardless of their values.  Sorting is not
   affected for the simulated NLS.

   In addition, with both real and simulated NLS, all printable characters
   in the range \200-\377, i.e., those  that  have  M-char  bindings,  are
   automatically   rebound   to  self-insert-command.   The  corresponding
   binding for the escape-char sequence, if any,  is  left  alone.   These
   characters are not rebound if the NOREBIND environment variable is set.
   This may be useful for the simulated NLS or a primitive real NLS  which
   assumes  full  ISO 8859-1.  Otherwise, all M-char bindings in the range
   \240-\377 are effectively undone.  Explicitly  rebinding  the  relevant
   keys with bindkey is of course still possible.

   Unknown  characters (i.e., those that are neither printable nor control
   characters) are printed in the format \nnn.  If the tty is not in 8 bit
   mode,  other  8  bit characters are printed by converting them to ASCII
   and using standout mode.  The shell never changes the 7/8 bit  mode  of
   the  tty  and tracks user-initiated changes of 7/8 bit mode.  NLS users
   (or, for that matter, those who want to use a meta  key)  may  need  to
   explicitly  set  the  tty in 8 bit mode through the appropriate stty(1)
   command in, e.g., the ~/.login file.

   OS variant support (+)
   A number of new builtin commands are provided to  support  features  in
   particular  operating  systems.   All  are  described  in detail in the
   Builtin commands section.

   On  systems  that  support  TCF  (aix-ibm370,  aix-ps2),  getspath  and
   setspath  get  and set the system execution path, getxvers and setxvers
   get and set  the  experimental  version  prefix  and  migrate  migrates
   processes  between  sites.   The  jobs builtin prints the site on which
   each job is executing.

   Under BS2000, bs2cmd executes commands  of  the  underlying  BS2000/OSD
   operating system.

   Under   Domain/OS,   inlib   adds   shared  libraries  to  the  current
   environment, rootnode changes the rootnode and ver changes the systype.

   Under Mach, setpath is equivalent to Mach's setpath(1).

   Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

   Under Harris CX/UX, ucb or att  runs  a  command  under  the  specified

   Under Convex/OS, warp prints or sets the universe.

   The   VENDOR,   OSTYPE  and  MACHTYPE  environment  variables  indicate
   respectively  the   vendor,   operating   system   and   machine   type
   (microprocessor  class  or  machine  model)  of the system on which the
   shell thinks it is running.  These are particularly useful when sharing
   one's  home  directory  between several types of machines; one can, for

       set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

   in one's ~/.login and put executables compiled for each machine in  the
   appropriate directory.

   The  version shell variable indicates what options were chosen when the
   shell was compiled.

   Note  also  the  newgrp  builtin,  the  afsuser  and  echo_style  shell
   variables and the system-dependent locations of the shell's input files
   (see FILES).

   Signal handling
   Login shells ignore interrupts when reading the  file  ~/.logout.   The
   shell  ignores quit signals unless started with -q.  Login shells catch
   the terminate  signal,  but  non-login  shells  inherit  the  terminate
   behavior  from  their parents.  Other signals have the values which the
   shell inherited from its parent.

   In shell scripts, the  shell's  handling  of  interrupt  and  terminate
   signals  can be controlled with onintr, and its handling of hangups can
   be controlled with hup and nohup.

   The shell exits on a hangup (see also the logout shell  variable).   By
   default,  the shell's children do too, but the shell does not send them
   a hangup when it exits.  hup arranges for the shell to send a hangup to
   a child when it exits, and nohup sets a child to ignore hangups.

   Terminal management (+)
   The  shell  uses  three  different  sets  of  terminal (``tty'') modes:
   `edit',  used  when  editing,  `quote',  used  when   quoting   literal
   characters,  and  `execute',  used  when executing commands.  The shell
   holds some settings in each mode constant, so commands which leave  the
   tty  in  a  confused  state do not interfere with the shell.  The shell
   also matches changes in the speed and padding of the tty.  The list  of
   tty  modes that are kept constant can be examined and modified with the
   setty builtin.  Note that although the editor uses CBREAK mode (or  its
   equivalent), it takes typed-ahead characters anyway.

   The  echotc,  settc  and  telltc commands can be used to manipulate and
   debug terminal capabilities from the command line.

   On systems that support SIGWINCH or  SIGWINDOW,  the  shell  adapts  to
   window  resizing  automatically  and  adjusts the environment variables
   LINES and COLUMNS if set.  If the environment variable TERMCAP contains
   li#  and  co#  fields, the shell adjusts them to reflect the new window


   The next sections of this manual describe all of the available  Builtin
   commands, Special aliases and Special shell variables.

   Builtin commands
   %job    A synonym for the fg builtin command.

   %job &  A synonym for the bg builtin command.

   :       Does nothing, successfully.

   @ name = expr
   @ name[index] = expr
   @ name++|--
   @ name[index]++|--
           The first form prints the values of all shell variables.

           The  second  form assigns the value of expr to name.  The third
           form assigns the value of expr to  the  index'th  component  of
           name; both name and its index'th component must already exist.

           expr  may  contain  the  operators `*', `+', etc., as in C.  If
           expr contains `<', `>', `&' or `' then at least  that  part  of
           expr  must be placed within `()'.  Note that the syntax of expr
           has nothing to do with that described under Expressions.

           The fourth and fifth forms increment (`++') or decrement (`--')
           name or its index'th component.

           The space between `@' and name is required.  The spaces between
           name and `=' and between `=' and expr are optional.  Components
           of expr must be separated by spaces.

   alias [name [wordlist]]
           Without  arguments,  prints all aliases.  With name, prints the
           alias for name.  With name and wordlist,  assigns  wordlist  as
           the   alias   of   name.   wordlist  is  command  and  filename
           substituted.  name may not be `alias' or `unalias'.   See  also
           the unalias builtin command.

   alloc   Shows  the  amount of dynamic memory acquired, broken down into
           used and free memory.  With an argument  shows  the  number  of
           free  and  used  blocks  in each size category.  The categories
           start at size 8 and double at each step.  This command's output
           may  vary  across  system types, because systems other than the
           VAX may use a different memory allocator.

   bg [%job ...]
           Puts the specified jobs (or,  without  arguments,  the  current
           job)  into  the  background,  continuing each if it is stopped.
           job may be a number, a string, `', `%', `+' or `-' as described
           under Jobs.

   bindkey [-l|-d|-e|-v|-u] (+)
   bindkey [-a] [-b] [-k] [-r] [--] key (+)
   bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
           Without  options,  the  first form lists all bound keys and the
           editor command to which each is bound, the  second  form  lists
           the  editor  command  to  which key is bound and the third form
           binds the editor command command to key.  Options include:

           -l  Lists all editor commands and a short description of each.
           -d  Binds all keys to the standard  bindings  for  the  default
           -e  Binds all keys to the standard GNU Emacs-like bindings.
           -v  Binds all keys to the standard vi(1)-like bindings.
           -a  Lists  or  changes key-bindings in the alternative key map.
               This is the key map used in vi command mode.
           -b  key  is  interpreted  as  a   control   character   written
               ^character  (e.g.,  `^A')  or  C-character (e.g., `C-A'), a
               meta  character  written  M-character  (e.g.,   `M-A'),   a
               function  key  written  F-string  (e.g., `F-string'), or an
               extended prefix key written X-character (e.g., `X-A').
           -k  key is interpreted as a symbolic arrow key name, which  may
               be one of `down', `up', `left' or `right'.
           -r  Removes  key's  binding.  Be careful: `bindkey -r' does not
               bind key to  self-insert-command  (q.v.),  it  unbinds  key
           -c  command  is  interpreted  as  a builtin or external command
               instead of an editor command.
           -s  command is  taken  as  a  literal  string  and  treated  as
               terminal  input  when  key is typed.  Bound keys in command
               are themselves reinterpreted, and this  continues  for  ten
               levels of interpretation.
           --  Forces  a break from option processing, so the next word is
               taken as key even if it begins with '-'.
           -u (or any invalid option)
               Prints a usage message.

           key may be a single character or a string.   If  a  command  is
           bound  to  a string, the first character of the string is bound
           to sequence-lead-in and the  entire  string  is  bound  to  the

           Control  characters in key can be literal (they can be typed by
           preceding them with the editor command quoted-insert,  normally
           bound  to  `^V')  or written caret-character style, e.g., `^A'.
           Delete is written `^?'  (caret-question mark).  key and command
           can  contain  backslashed  escape  sequences  (in  the style of
           System V echo(1)) as follows:

               \e      Escape
               \f      Form feed
               \n      Newline
               \r      Carriage return
               \t      Horizontal tab
               \v      Vertical tab
               \nnn    The ASCII  character  corresponding  to  the  octal
                       number nnn

           `\'  nullifies  the special meaning of the following character,
           if it has any, notably `\' and `^'.

   bs2cmd bs2000-command (+)
           Passes bs2000-command to the  BS2000  command  interpreter  for
           execution.  Only  non-interactive commands can be executed, and
           it is not possible to execute any command  that  would  overlay
           the  image  of  the  current  process,  like /EXECUTE or /CALL-
           PROCEDURE. (BS2000 only)

   break   Causes execution  to  resume  after  the  end  of  the  nearest
           enclosing  foreach  or  while.   The  remaining commands on the
           current  line  are  executed.   Multi-level  breaks  are   thus
           possible by writing them all on one line.

   breaksw Causes a break from a switch, resuming after the endsw.

   builtins (+)
           Prints the names of all builtin commands.

   bye (+) A  synonym  for  the logout builtin command.  Available only if
           the shell was so compiled; see the version shell variable.

   case label:
           A label in a switch statement as discussed below.

   cd [-p] [-l] [-n|-v] [I--] [name]
           If a directory name  is  given,  changes  the  shell's  working
           directory to name.  If not, changes to home.  If name is `-' it
           is interpreted as the previous  working  directory  (see  Other
           substitutions).   (+)  If  name  is  not  a subdirectory of the
           current directory (and does not begin with `/', `./' or `../'),
           each  component  of the variable cdpath is checked to see if it
           has a subdirectory name.  Finally, if all else fails  but  name
           is  a  shell variable whose value begins with `/', then this is
           tried to see if it is a directory.

           With -p, prints the final directory stack, just like dirs.  The
           -l,  -n and -v flags have the same effect on cd as on dirs, and
           they imply -p.   (+)  Using  --  forces  a  break  from  option
           processing so the next word is taken as the directory name even
           if it begins with '-'. (+)

           See also the implicitcd shell variable.

   chdir   A synonym for the cd builtin command.

   complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
           Without arguments, lists all completions.  With command,  lists
           completions  for  command.  With command and word etc., defines

           command may be a full  command  name  or  a  glob-pattern  (see
           Filename substitution).  It can begin with `-' to indicate that
           completion should be used only when command is ambiguous.

           word specifies which word relative to the current word is to be
           completed, and may be one of the following:

               c   Current-word  completion.   pattern  is  a glob-pattern
                   which must match the beginning of the current  word  on
                   the  command  line.  pattern is ignored when completing
                   the current word.
               C   Like  c,  but  includes  pattern  when  completing  the
                   current word.
               n   Next-word  completion.  pattern is a glob-pattern which
                   must match the beginning of the previous  word  on  the
                   command line.
               N   Like  n,  but  must match the beginning of the word two
                   before the current word.
               p   Position-dependent completion.  pattern  is  a  numeric
                   range,  with  the  same  syntax  used  to  index  shell
                   variables, which must include the current word.

           list, the list of possible  completions,  may  be  one  of  the

               a       Aliases
               b       Bindings (editor commands)
               c       Commands (builtin or external commands)
               C       External  commands  which  begin  with the supplied
                       path prefix
               d       Directories
               D       Directories which  begin  with  the  supplied  path
               e       Environment variables
               f       Filenames
               F       Filenames which begin with the supplied path prefix
               g       Groupnames
               j       Jobs
               l       Limits
               n       Nothing
               s       Shell variables
               S       Signals
               t       Plain (``text'') files
               T       Plain   (``text'')   files  which  begin  with  the
                       supplied path prefix
               v       Any variables
               u       Usernames
               x       Like n, but  prints  select  when  list-choices  is
               X       Completions
               $var    Words from the variable var
               (...)   Words from the given list
               `...`   Words from the output of command

           select  is an optional glob-pattern.  If given, words from only
           list that match select are considered  and  the  fignore  shell
           variable  is  ignored.   The last three types of completion may
           not have a select pattern, and x uses select as an  explanatory
           message when the list-choices editor command is used.

           suffix  is  a  single  character to be appended to a successful
           completion.  If null, no character is appended.  If omitted (in
           which  case  the fourth delimiter can also be omitted), a slash
           is appended to directories and a space to other words.

           command invoked from `...` version has  additional  environment
           variable  set,  the  variable name is COMMAND_LINE and contains
           (as its name indicates) contents of the current (already  typed
           in)  command  line.  One  can  examine  and use contents of the
           COMMAND_LINE variable  in  her  custom  script  to  build  more
           sophisticated  completions  (see completion for svn(1) included
           in this package).

           Now for some examples.  Some commands take only directories  as
           arguments, so there's no point completing plain files.

               > complete cd 'p/1/d/'

           completes  only  the  first  word following `cd' (`p/1') with a
           directory.  p-type completion can also be used to  narrow  down
           command completion:

               > co[^D]
               complete compress
               > complete -co* 'p/0/(compress)/'
               > co[^D]
               > compress

           This completion completes commands (words in position 0, `p/0')
           which begin with `co' (thus matching `co*') to `compress'  (the
           only  word  in  the list).  The leading `-' indicates that this
           completion is to be used with only ambiguous commands.

               > complete find 'n/-user/u/'

           is an example of n-type completion.  Any word following  `find'
           and immediately following `-user' is completed from the list of

               > complete cc 'c/-I/d/'

           demonstrates c-type completion.  Any word  following  `cc'  and
           beginning  with  `-I' is completed as a directory.  `-I' is not
           taken as part of the directory because we used lowercase c.

           Different lists are useful with different commands.

               > complete alias 'p/1/a/'
               > complete man 'p/*/c/'
               > complete set 'p/1/s/'
               > complete true 'p/1/x:Truth has no options./'

           These complete words following `alias' with aliases, `man' with
           commands,  and `set' with shell variables.  `true' doesn't have
           any options, so x does nothing when completion is attempted and
           prints  `Truth  has  no  options.'  when completion choices are

           Note that the man example, and several  other  examples  below,
           could just as well have used 'c/*' or 'n/*' as 'p/*'.

           Words  can be completed from a variable evaluated at completion

               > complete ftp 'p/1/$hostnames/'
               > set hostnames = (
               > ftp [^D]
               > ftp [^C]
               >  set  hostnames  =   (
               > ftp [^D]

           or from a command run at completion time:

               > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
               > kill -9 [^D]
               23113 23377 23380 23406 23429 23529 23530 PID

           Note  that  the  complete  command  does  not  itself quote its
           arguments, so the braces, space and `$' in `{print $1}' must be
           quoted explicitly.

           One command can have multiple completions:

               > complete dbx 'p/2/(core)/' 'p/*/c/'

           completes the second argument to `dbx' with the word `core' and
           all other arguments with commands.  Note  that  the  positional
           completion   is  specified  before  the  next-word  completion.
           Because completions are evaluated from left to  right,  if  the
           next-word completion were specified first it would always match
           and the positional completion would never be executed.  This is
           a common mistake when defining a completion.

           The  select  pattern  is useful when a command takes files with
           only particular forms as arguments.  For example,

               > complete cc 'p/*/f:*.[cao]/'

           completes `cc' arguments to files ending in only `.c', `.a', or
           `.o'.  select can also exclude files, using negation of a glob-
           pattern as described under Filename  substitution.   One  might

               > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

           to  exclude  precious  source  code  from  `rm' completion.  Of
           course,  one  could  still  type  excluded  names  manually  or
           override  the  completion mechanism using the complete-word-raw
           or list-choices-raw editor commands (q.v.).

           The `C', `D', `F' and `T' lists are like `c', `d', `f' and  `t'
           respectively,  but  they use the select argument in a different
           way:  to  restrict  completion  to  files  beginning   with   a
           particular path prefix.  For example, the Elm mail program uses
           `=' as an abbreviation for one's mail directory.  One might use

               > complete elm c@=@F:$HOME/Mail/@

           to complete `elm -f =' as if it were `elm  -f  ~/Mail/'.   Note
           that  we  used  `@'  instead of `/' to avoid confusion with the
           select argument, and we used `$HOME'  instead  of  `~'  because
           home  directory  substitution  works at only the beginning of a

           suffix is used to add a nonstandard suffix (not  space  or  `/'
           for directories) to completed words.

               > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

           completes arguments to `finger' from the list of users, appends
           an `@', and then completes after the `@' from  the  `hostnames'
           variable.   Note  again  the order in which the completions are

           Finally, here's a complex example for inspiration:

               > complete find \
               'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
               n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
               'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
               'n/-type/(b c d f l p s)/' \
               c/-/(name newer cpio ncpio exec ok user \
               group fstype type atime ctime depth inum \
               ls mtime nogroup nouser perm print prune \
               size xdev)/' \

           This completes words following `-name',  `-newer',  `-cpio'  or
           `ncpio'  (note  the pattern which matches both) to files, words
           following `-exec' or `-ok' to commands, words following  `user'
           and   `group'  to  users  and  groups  respectively  and  words
           following `-fstype' or `-type' to members of the  given  lists.
           It  also  completes the switches themselves from the given list
           (note the use of c-type completion) and completes anything  not
           otherwise completed to a directory.  Whew.

           Remember  that  programmed  completions are ignored if the word
           being completed is a tilde substitution (beginning with `~') or
           a  variable  (beginning with `$').  complete is an experimental
           feature, and the syntax may change in future  versions  of  the
           shell.  See also the uncomplete builtin command.

           Continues  execution of the nearest enclosing while or foreach.
           The rest of the commands on the current line are executed.

           Labels the default case in a switch statement.  It should  come
           after all case labels.

   dirs [-l] [-n|-v]
   dirs -S|-L [filename] (+)
   dirs -c (+)
           The  first  form  prints  the  directory stack.  The top of the
           stack is at the left and the first directory in  the  stack  is
           the  current  directory.  With -l, `~' or `~name' in the output
           is expanded explicitly to home or  the  pathname  of  the  home
           directory  for  user  name.   (+)  With -n, entries are wrapped
           before they reach the edge of the screen.  (+) With -v, entries
           are  printed  one  per line, preceded by their stack positions.
           (+) If more than one of -n or -v is given, -v takes precedence.
           -p is accepted but does nothing.

           With  -S, the second form saves the directory stack to filename
           as a series of cd and  pushd  commands.   With  -L,  the  shell
           sources  filename,  which  is presumably a directory stack file
           saved by the -S option or the savedirs  mechanism.   In  either
           case,  dirsfile is used if filename is not given and ~/.cshdirs
           is used if dirsfile is unset.

           Note that login shells  do  the  equivalent  of  `dirs  -L'  on
           startup  and,  if  savedirs  is  set, `dirs -S' before exiting.
           Because only ~/.tcshrc is normally sourced  before  ~/.cshdirs,
           dirsfile should be set in ~/.tcshrc rather than ~/.login.

           The last form clears the directory stack.

   echo [-n] word ...
           Writes  each  word to the shell's standard output, separated by
           spaces and terminated with a  newline.   The  echo_style  shell
           variable  may  be  set to emulate (or not) the flags and escape
           sequences of the BSD and/or System  V  versions  of  echo;  see

   echotc [-sv] arg ... (+)
           Exercises  the  terminal capabilities (see termcap(5)) in args.
           For example,  'echotc  home'  sends  the  cursor  to  the  home
           position, 'echotc cm 3 10' sends it to column 3 and row 10, and
           'echotc ts 0; echo "This is a test."; echotc fs'  prints  "This
           is a test."  in the status line.

           If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
           value of that capability ("yes" or  "no"  indicating  that  the
           terminal does or does not have that capability).  One might use
           this to make the output from a shell  script  less  verbose  on
           slow  terminals, or limit command output to the number of lines
           on the screen:

               > set history=`echotc lines`

               > @ history--
           Termcap strings may  contain  wildcards  which  will  not  echo
           correctly.   One  should use double quotes when setting a shell
           variable to a terminal capability string, as in  the  following
           example that places the date in the status line:

               > set tosl="`echotc ts 0`"
               > set frsl="`echotc fs`"
               > echo -n "$tosl";date; echo -n "$frsl"

           With  -s,  nonexistent  capabilities  return  the  empty string
           rather than causing an error.  With -v, messages are verbose.

   endsw   See the description of  the  foreach,  if,  switch,  and  while
           statements below.

   eval arg ...
           Treats  the  arguments  as  input to the shell and executes the
           resulting command(s) in the context of the current shell.  This
           is  usually used to execute commands generated as the result of
           command or variable substitution, because parsing occurs before
           these substitutions.  See tset(1) for a sample use of eval.

   exec command
           Executes the specified command in place of the current shell.

   exit [expr]
           The shell exits either with the value of the specified expr (an
           expression, as described under Expressions) or,  without  expr,
           with the value 0.

   fg [%job ...]
           Brings  the  specified jobs (or, without arguments, the current
           job) into the foreground, continuing each  if  it  is  stopped.
           job may be a number, a string, `', `%', `+' or `-' as described
           under Jobs.  See also the run-fg-editor editor command.

   filetest -op file ... (+)
           Applies op (which is a file inquiry operator as described under
           File inquiry operators) to each file and returns the results as
           a space-separated list.

   foreach name (wordlist)
   end     Successively sets the variable name to each member of  wordlist
           and  executes the sequence of commands between this command and
           the matching end.  (Both foreach and end must appear  alone  on
           separate  lines.)   The builtin command continue may be used to
           continue the loop prematurely and the builtin command break  to
           terminate  it  prematurely.  When this command is read from the
           terminal, the loop is read once prompting with `foreach? '  (or
           prompt2)  before  any  statements in the loop are executed.  If
           you make a mistake typing in a loop at the terminal you can rub
           it out.

   getspath (+)
           Prints the system execution path.  (TCF only)

   getxvers (+)
           Prints the experimental version prefix.  (TCF only)

   glob wordlist
           Like  echo,  but the `-n' parameter is not recognized and words
           are delimited by null characters in  the  output.   Useful  for
           programs  which wish to use the shell to filename expand a list
           of words.

   goto word
           word is filename and command-substituted to yield a  string  of
           the  form  `label'.   The  shell  rewinds  its input as much as
           possible, searches for a line of the  form  `label:',  possibly
           preceded  by blanks or tabs, and continues execution after that

           Prints a statistics line indicating how effective the  internal
           hash table has been at locating commands (and avoiding exec's).
           An exec is attempted for each component of the path  where  the
           hash  function  indicates a possible hit, and in each component
           which does not begin with a `/'.

           On machines without vfork(2), prints only the number  and  size
           of hash buckets.

   history [-hTr] [n]
   history -S|-L|-M [filename] (+)
   history -c (+)
           The  first  form  prints the history event list.  If n is given
           only the n most recent events are printed or saved.   With  -h,
           the  history list is printed without leading numbers.  If -T is
           specified, timestamps are printed also in comment form.   (This
           can be used to produce files suitable for loading with 'history
           -L' or 'source -h'.)  With -r, the order of  printing  is  most
           recent first rather than oldest first.

           With  -S,  the  second form saves the history list to filename.
           If the first word of the savehist shell variable is  set  to  a
           number,  at most that many lines are saved.  If the second word
           of savehist is set to `merge', the history list is merged  with
           the  existing history file instead of replacing it (if there is
           one) and sorted by time stamp.  (+) Merging is intended for  an
           environment  like  the  X  Window System with several shells in
           simultaneous use.  Currently it succeeds only when  the  shells
           quit nicely one after another.

           With  -L,  the  shell  appends  filename, which is presumably a
           history list saved by the -S option or the savehist  mechanism,
           to  the  history  list.   -M  is  like  -L, but the contents of
           filename are  merged  into  the  history  list  and  sorted  by
           timestamp.  In either case, histfile is used if filename is not
           given and ~/.history is used if histfile  is  unset.   `history
           -L' is exactly like 'source -h' except that it does not require
           a filename.

           Note that login shells do the equivalent  of  `history  -L'  on
           startup  and,  if savehist is set, `history -S' before exiting.
           Because only ~/.tcshrc is normally sourced  before  ~/.history,
           histfile should be set in ~/.tcshrc rather than ~/.login.

           If  histlit  is  set, the first and second forms print and save
           the literal (unexpanded) form of the history list.

           The last form clears the history list.

   hup [command] (+)
           With command, runs command such that it will exit on  a  hangup
           signal  and  arranges  for the shell to send it a hangup signal
           when the shell exits.  Note that commands  may  set  their  own
           response  to  hangups,  overriding  hup.   Without an argument,
           causes the non-interactive shell only to exit on a  hangup  for
           the  remainder of the script.  See also Signal handling and the
           nohup builtin command.

   if (expr) command
           If  expr  (an  expression,  as  described  under   Expressions)
           evaluates   true,   then   command   is   executed.    Variable
           substitution on command happens early, at the same time it does
           for  the  rest  of  the  if  command.  command must be a simple
           command, not  an  alias,  a  pipeline,  a  command  list  or  a
           parenthesized   command   list,  but  it  may  have  arguments.
           Input/output redirection occurs  even  if  expr  is  false  and
           command is thus not executed; this is a bug.

   if (expr) then
   else if (expr2) then
   endif   If  the  specified  expr is true then the commands to the first
           else are executed; otherwise if expr2 is true then the commands
           to  the  second  else are executed, etc.  Any number of else-if
           pairs are possible; only one endif is needed.  The else part is
           likewise  optional.   (The  words else and endif must appear at
           the beginning of input lines; the if must appear alone  on  its
           input line or after an else.)

   inlib shared-library ... (+)
           Adds  each shared-library to the current environment.  There is
           no way to remove a shared library.  (Domain/OS only)

   jobs [-l]
           Lists the active jobs.  With -l, lists process IDs in  addition
           to  the normal information.  On TCF systems, prints the site on
           which each job is executing.

   kill [-s signal] %job|pid ...
   kill -l The first and second forms sends the specified signal  (or,  if
           none  is  given,  the TERM (terminate) signal) to the specified
           jobs or processes.  job may be a number, a string, `', `%', `+'
           or  `-'  as  described under Jobs.  Signals are either given by
           number or by name (as given in /usr/include/signal.h,  stripped
           of  the  prefix  `SIG').   There is no default job; saying just
           `kill' does not send a signal  to  the  current  job.   If  the
           signal being sent is TERM (terminate) or HUP (hangup), then the
           job or process is sent a CONT (continue) signal as  well.   The
           third form lists the signal names.

   limit [-h] [resource [maximum-use]]
           Limits  the consumption by the current process and each process
           it creates  to  not  individually  exceed  maximum-use  on  the
           specified  resource.   If  no  maximum-use  is  given, then the
           current limit is printed; if no resource  is  given,  then  all
           limitations  are  given.   If  the  -h  flag is given, the hard
           limits are used instead of the current limits.  The hard limits
           impose a ceiling on the values of the current limits.  Only the
           super-user may raise the hard limits, but a user may  lower  or
           raise the current limits within the legal range.

           Controllable  resources  currently include (if supported by the

                  the maximum number of cpu-seconds to  be  used  by  each

                  the largest single file which can be created

                  the  maximum growth of the data+stack region via sbrk(2)
                  beyond the end of the program text

                  the maximum size  of  the  automatically-extended  stack

                  the size of the largest core dump that will be created

                  the maximum amount of physical memory a process may have
                  allocated to it at a given time

                  the maximum amount of virtual memory a process may  have
                  allocated to it at a given time (address space)

                  the  maximum amount of virtual memory a process may have
                  allocated to it at a given time

                  the maximum amount of memory a process may allocate  per
                  brk() system call

           descriptors or openfiles
                  the maximum number of open files for this process

                  the maximum number of threads for this process

                  the  maximum  size  which a process may lock into memory
                  using mlock(2)

                  the maximum number of simultaneous  processes  for  this
                  user id

           sbsize the maximum size of socket buffer usage for this user

                  the  maximum  amount  of swap space reserved or used for
                  this user

                  the maximum number of locks for this user

                  the maximum number of pending signals for this user

                  the maximum number of bytes in POSIX  mqueues  for  this

                  the  maximum  nice priority the user is allowed to raise
                  mapped from [19...-20] to [0...39] for this user

                  the maximum realtime priority for  this  user  maxrttime
                  the timeout for RT tasks in microseconds for this user.

           maximum-use  may  be  given  as  a  (floating point or integer)
           number followed by a scale factor.  For all limits  other  than
           cputime the default scale is `k' or `kilobytes' (1024 bytes); a
           scale factor of `m' or `megabytes' or `g'  or  `gigabytes'  may
           also  be  used.   For cputime the default scaling is `seconds',
           while `m' for minutes or `h' for hours, or a time of  the  form
           `mm:ss' giving minutes and seconds may be used.

           If  maximum-use   is  `unlimited',  then  the limitation on the
           specified resource  is  removed  (this  is  equivalent  to  the
           unlimit builtin command).

           For both resource names and scale factors, unambiguous prefixes
           of the names suffice.

   log (+) Prints the watch  shell  variable  and  reports  on  each  user
           indicated  in  watch  who is logged in, regardless of when they
           last logged in.  See also watchlog.

   login   Terminates a login shell, replacing  it  with  an  instance  of
           /bin/login.   This   is  one  way  to  log  off,  included  for
           compatibility with sh(1).

   logout  Terminates a login shell.  Especially useful  if  ignoreeof  is

   ls-F [-switch ...] [file ...] (+)
           Lists  files like `ls -F', but much faster.  It identifies each
           type of special file in the listing with a special character:

           /   Directory
           *   Executable
           #   Block device
           %   Character device
           |   Named pipe (systems with named pipes only)
           =   Socket (systems with sockets only)
           @   Symbolic link (systems with symbolic links only)
           +   Hidden directory (AIX only)  or  context  dependent  (HP/UX
           :   Network special (HP/UX only)

           If  the  listlinks  shell  variable  is set, symbolic links are
           identified in more detail (on only systems that have  them,  of

           @   Symbolic link to a non-directory
           >   Symbolic link to a directory
           &   Symbolic link to nowhere

           listlinks  also  slows  down ls-F and causes partitions holding
           files pointed to by symbolic links to be mounted.

           If the listflags shell variable is set to `x', `a' or  `A',  or
           any combination thereof (e.g., `xA'), they are used as flags to
           ls-F, making it act like `ls -xF', `ls  -Fa',  `ls  -FA'  or  a
           combination  (e.g.,  `ls  -FxA').  On machines where `ls -C' is
           not the default, ls-F acts  like  `ls  -CF',  unless  listflags
           contains  an  `x',  in  which case it acts like `ls -xF'.  ls-F
           passes its arguments to ls(1) if it is given any  switches,  so
           `alias ls ls-F' generally does the right thing.

           The   ls-F  builtin  can  list  files  using  different  colors
           depending on the filetype or extension.  See  the  color  shell
           variable and the LS_COLORS environment variable.

   migrate [-site] pid|%jobid ... (+)
   migrate -site (+)
           The  first  form  migrates  the  process  or  job  to  the site
           specified or the default site determined by  the  system  path.
           The  second  form  is  equivalent  to  `migrate  -site  $$': it
           migrates the current process to the specified site.   Migrating
           the  shell  itself  can  cause unexpected behavior, because the
           shell does not like to lose its tty.  (TCF only)

   newgrp [-] [group] (+)
           Equivalent to `exec newgrp'; see newgrp(1).  Available only  if
           the shell was so compiled; see the version shell variable.

   nice [+number] [command]
           Sets  the  scheduling  priority  for  the  shell to number, or,
           without number, to  4.   With  command,  runs  command  at  the
           appropriate priority.  The greater the number, the less cpu the
           process gets.  The super-user may specify negative priority  by
           using `nice -number ...'.  Command is always executed in a sub-
           shell, and the restrictions placed on  commands  in  simple  if
           statements apply.

   nohup [command]
           With  command,  runs  command  such  that it will ignore hangup
           signals.  Note that commands may  set  their  own  response  to
           hangups,  overriding  nohup.   Without  an argument, causes the
           non-interactive shell only to ignore hangups for the  remainder
           of  the  script.   See also Signal handling and the hup builtin

   notify [%job ...]
           Causes the shell to notify the  user  asynchronously  when  the
           status  of  any  of  the  specified jobs (or, without %job, the
           current job) changes, instead of waiting until the next  prompt
           as  is  usual.   job may be a number, a string, `', `%', `+' or
           `-' as  described  under  Jobs.   See  also  the  notify  shell

   onintr [-|label]
           Controls  the  action  of  the  shell  on  interrupts.  Without
           arguments,  restores  the  default  action  of  the  shell   on
           interrupts, which is to terminate shell scripts or to return to
           the  terminal  command  input  level.   With  `-',  causes  all
           interrupts  to  be  ignored.   With  label, causes the shell to
           execute a `goto label' when an interrupt is received or a child
           process terminates because it was interrupted.

           onintr  is  ignored  if  the  shell  is running detached and in
           system startup files (see FILES), where interrupts are disabled

   popd [-p] [-l] [-n|-v] [+n]
           Without  arguments, pops the directory stack and returns to the
           new top directory.  With a number `+n', discards the n'th entry
           in the stack.

           Finally,  all  forms  of  popd print the final directory stack,
           just like dirs.  The pushdsilent shell variable can be  set  to
           prevent  this  and  the  -p  flag  can  be  given  to  override
           pushdsilent.  The -l, -n and -v flags have the same  effect  on
           popd as on dirs.  (+)

   printenv [name] (+)
           Prints  the  names  and values of all environment variables or,
           with name, the value of the environment variable name.

   pushd [-p] [-l] [-n|-v] [name|+n]
           Without arguments,  exchanges  the  top  two  elements  of  the
           directory   stack.    If  pushdtohome  is  set,  pushd  without
           arguments does `pushd ~', like cd.  (+) With name,  pushes  the
           current  working directory onto the directory stack and changes
           to name.  If name is `-' it  is  interpreted  as  the  previous
           working  directory (see Filename substitution).  (+) If dunique
           is set, pushd removes any instances  of  name  from  the  stack
           before  pushing  it  onto  the  stack.  (+) With a number `+n',
           rotates the nth element of the directory stack around to be the
           top  element  and  changes to it.  If dextract is set, however,
           `pushd +n' extracts the nth directory, pushes it onto  the  top
           of the stack and changes to it.  (+)

           Finally,  all  forms  of pushd print the final directory stack,
           just like dirs.  The pushdsilent shell variable can be  set  to
           prevent  this  and  the  -p  flag  can  be  given  to  override
           pushdsilent.  The -l, -n and -v flags have the same  effect  on
           pushd as on dirs.  (+)

   rehash  Causes   the  internal  hash  table  of  the  contents  of  the
           directories in the path variable to  be  recomputed.   This  is
           needed  if  the  autorehash  shell  variable is not set and new
           commands are added to directories in path while you are  logged
           in.    With   autorehash,   a   new   command   will  be  found
           automatically, except in the special case where another command
           of  the  same  name  which  is located in a different directory
           already exists in the hash table.  Also flushes  the  cache  of
           home directories built by tilde expansion.

   repeat count command
           The   specified   command,   which   is  subject  to  the  same
           restrictions as the command in the one line if statement above,
           is  executed count times.  I/O redirections occur exactly once,
           even if count is 0.

   rootnode //nodename (+)
           Changes the  rootnode  to  //nodename,  so  that  `/'  will  be
           interpreted as `//nodename'.  (Domain/OS only)

   sched (+)
   sched [+]hh:mm command (+)
   sched -n (+)
           The  first  form  prints  the  scheduled-event list.  The sched
           shell variable may be set to define the  format  in  which  the
           scheduled-event  list is printed.  The second form adds command
           to the scheduled-event list.  For example,

               > sched 11:00 echo It\'s eleven o\'clock.

           causes the shell to echo `It's eleven o'clock.' at 11 AM.   The
           time may be in 12-hour AM/PM format

               > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

           or may be relative to the current time:

               > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

           A  relative  time  specification may not use AM/PM format.  The
           third form removes item n from the event list:

               > sched
                    1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                    2  Wed Apr  4 17:00  set prompt=[%h] It's after 5;  go
               home: >
               > sched -2
               > sched
                    1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

           A  command  in the scheduled-event list is executed just before
           the first prompt is printed after the time when the command  is
           scheduled.   It  is  possible  to  miss the exact time when the
           command is to be run, but an overdue command  will  execute  at
           the  next prompt.  A command which comes due while the shell is
           waiting for  user  input  is  executed  immediately.   However,
           normal  operation  of  an  already-running  command will not be
           interrupted so that a scheduled-event list element may be run.

           This mechanism is similar to, but not the same  as,  the  at(1)
           command  on  some Unix systems.  Its major disadvantage is that
           it may not run a command at exactly the  specified  time.   Its
           major  advantage  is  that because sched runs directly from the
           shell, it has access to shell variables and  other  structures.
           This   provides   a   mechanism   for  changing  one's  working
           environment based on the time of day.

   set name ...
   set name=word ...
   set [-r] [-f|-l] name=(wordlist) ... (+)
   set name[index]=word ...
   set -r (+)
   set -r name ... (+)
   set -r name=word ... (+)
           The first form of the command prints the  value  of  all  shell
           variables.   Variables  which  contain  more than a single word
           print as a parenthesized word list.  The second form sets  name
           to  the  null  string.   The third form sets name to the single
           word.  The fourth form sets  name  to  the  list  of  words  in
           wordlist.   In  all  cases  the  value  is command and filename
           expanded.  If -r is specified, the value is set read-only.   If
           -f  or  -l  are  specified, set only unique words keeping their
           order.  -f prefers the first occurrence of a word, and  -l  the
           last.   The  fifth  form sets the index'th component of name to
           word; this component must already exist.  The sixth form  lists
           only  the names of all shell variables that are read-only.  The
           seventh form makes name read-only, whether  or  not  it  has  a
           value.  The eighth form is the same as the third form, but make
           name read-only at the same time.

           These arguments can be repeated to set  and/or  make  read-only
           multiple  variables  in  a  single set command.  Note, however,
           that variable expansion happens for all  arguments  before  any
           setting  occurs.   Note  also  that `=' can be adjacent to both
           name and word or separated from both by whitespace, but  cannot
           be  adjacent  to  only  one  or  the other.  See also the unset
           builtin command.

   setenv [name [value]]
           Without  arguments,  prints  the  names  and  values   of   all
           environment   variables.   Given  name,  sets  the  environment
           variable name to value or, without value, to the null string.

   setpath path (+)
           Equivalent to setpath(1).  (Mach only)

   setspath LOCAL|site|cpu ... (+)
           Sets the system execution path.  (TCF only)

   settc cap value (+)
           Tells the shell to believe that the terminal capability cap (as
           defined in termcap(5)) has the value value.  No sanity checking
           is done.  Concept terminal users may have to `settc xn  no'  to
           get proper wrapping at the rightmost column.

   setty [-d|-q|-x] [-a] [[+|-]mode] (+)
           Controls  which  tty  modes (see Terminal management) the shell
           does not allow to change.  -d, -q or -x tells setty to  act  on
           the `edit', `quote' or `execute' set of tty modes respectively;
           without -d, -q or -x, `execute' is used.

           Without other arguments, setty lists the modes  in  the  chosen
           set  which  are  fixed  on  (`+mode')  or  off  (`-mode').  The
           available modes, and thus the  display,  vary  from  system  to
           system.  With -a, lists all tty modes in the chosen set whether
           or not they are fixed.  With +mode, -mode or mode,  fixes  mode
           on  or off or removes control from mode in the chosen set.  For
           example, `setty +echok echoe' fixes `echok' mode on and  allows
           commands to turn `echoe' mode on or off, both when the shell is
           executing commands.

   setxvers [string] (+)
           Set the experimental version prefix to string, or removes it if
           string is omitted.  (TCF only)

   shift [variable]
           Without  arguments,  discards argv[1] and shifts the members of
           argv to the left.  It is an error for argv not to be set or  to
           have  less than one word as value.  With variable, performs the
           same function on variable.

   source [-h] name [args ...]
           The shell reads and executes commands from name.  The  commands
           are  not  placed  on  the history list.  If any args are given,
           they are placed in argv.  (+) source commands may be nested; if
           they  are  nested  too  deeply  the  shell  may run out of file
           descriptors.  An error in a source at any level terminates  all
           nested  source  commands.   With -h, commands are placed on the
           history list instead of being executed, much like `history -L'.

   stop %job|pid ...
           Stops the specified jobs or processes which  are  executing  in
           the background.  job may be a number, a string, `', `%', `+' or
           `-' as described under Jobs.  There is no default  job;  saying
           just `stop' does not stop the current job.

   suspend Causes  the shell to stop in its tracks, much as if it had been
           sent a stop signal with ^Z.  This is most often  used  to  stop
           shells started by su(1).

   switch (string)
   case str1:
   endsw   Each  case label is successively matched, against the specified
           string which is first command and filename expanded.  The  file
           metacharacters  `*',  `?'  and `[...]'  may be used in the case
           labels, which are variable expanded.  If  none  of  the  labels
           match  before  a  `default'  label is found, then the execution
           begins after the  default  label.   Each  case  label  and  the
           default  label  must  appear  at  the beginning of a line.  The
           command breaksw causes execution to continue after  the  endsw.
           Otherwise  control  may  fall  through  case labels and default
           labels as in C.  If no label matches and there is  no  default,
           execution continues after the endsw.

   telltc (+)
           Lists the values of all terminal capabilities (see termcap(5)).

   termname [terminal type] (+)
           Tests  if  terminal  type  (or  the current value of TERM if no
           terminal type is given) has an entry in the hosts termcap(5) or
           terminfo(5)  database.  Prints  the terminal type to stdout and
           returns 0 if an entry is present otherwise returns 1.

   time [command]
           Executes command (which must be a simple command, not an alias,
           a pipeline, a command list or a parenthesized command list) and
           prints a time summary as described under the time variable.  If
           necessary,  an  extra  shell  is  created  to  print  the  time
           statistic when the command completes.  Without command,  prints
           a time summary for the current shell and its children.

   umask [value]
           Sets  the file creation mask to value, which is given in octal.
           Common values for the mask are 002, giving all  access  to  the
           group  and  read  and execute access to others, and 022, giving
           read and execute access  to  the  group  and  others.   Without
           value, prints the current file creation mask.

   unalias pattern
           Removes  all  aliases  whose  names match pattern.  `unalias *'
           thus removes all aliases.  It is not an error for nothing to be

   uncomplete pattern (+)
           Removes all completions whose names match pattern.  `uncomplete
           *' thus removes all  completions.   It  is  not  an  error  for
           nothing to be uncompleted.

   unhash  Disables  use  of  the internal hash table to speed location of
           executed programs.

   universe universe (+)
           Sets the universe to universe.  (Masscomp/RTU only)

   unlimit [-hf] [resource]
           Removes the limitation  on  resource  or,  if  no  resource  is
           specified,    all   resource   limitations.    With   -h,   the
           corresponding hard limits are removed.  Only the super-user may
           do this.  Note that unlimit may not exit successful, since most
           systems do not allow descriptors  to  be  unlimited.   With  -f
           errors are ignored.

   unset pattern
           Removes  all  variables  whose names match pattern, unless they
           are read-only.  `unset *' thus  removes  all  variables  unless
           they are read-only; this is a bad idea.  It is not an error for
           nothing to be unset.

   unsetenv pattern
           Removes all environment variables whose  names  match  pattern.
           `unsetenv  *' thus removes all environment variables; this is a
           bad idea.  It is not an error for nothing to be unsetenved.

   ver [systype [command]] (+)
           Without arguments, prints SYSTYPE.  With systype, sets  SYSTYPE
           to  systype.   With systype and command, executes command under
           systype.  systype may  be  `bsd4.3'  or  `sys5.3'.   (Domain/OS

   wait    The  shell  waits  for  all  background  jobs.  If the shell is
           interactive, an interrupt will disrupt the wait and  cause  the
           shell  to  print  the  names and job numbers of all outstanding

   warp universe (+)
           Sets the universe to universe.  (Convex/OS only)

   watchlog (+)
           An  alternate  name  for  the  log  builtin   command   (q.v.).
           Available  only  if  the shell was so compiled; see the version
           shell variable.

   where command (+)
           Reports all known  instances  of  command,  including  aliases,
           builtins and executables in path.

   which command (+)
           Displays  the  command that will be executed by the shell after
           substitutions, path searching, etc.   The  builtin  command  is
           just  like  which(1), but it correctly reports tcsh aliases and
           builtins and is 10 to 100 times faster.  See  also  the  which-
           command editor command.

   while (expr)
   end     Executes  the  commands  between the while and the matching end
           while expr (an  expression,  as  described  under  Expressions)
           evaluates  non-zero.   while and end must appear alone on their
           input lines.  break and continue may be used  to  terminate  or
           continue the loop prematurely.  If the input is a terminal, the
           user is prompted the  first  time  through  the  loop  as  with

   Special aliases (+)
   If  set,  each of these aliases executes automatically at the indicated
   time.  They are all initially undefined.

   beepcmd Runs when the shell wants to ring the terminal bell.

   cwdcmd  Runs after every change of working directory.  For example,  if
           the  user is working on an X window system using xterm(1) and a
           re-parenting window manager that supports title  bars  such  as
           twm(1) and does

               > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

           then the shell will change the title of the running xterm(1) to
           be the name of the host, a colon, and the full current  working
           directory.  A fancier way to do that is

               >          alias          cwdcmd          'echo          -n

           This will put the hostname and working directory on  the  title
           bar but only the hostname in the icon manager menu.

           Note  that  putting  a cd, pushd or popd in cwdcmd may cause an
           infinite loop.  It is the author's opinion that anyone doing so
           will get what they deserve.

   jobcmd  Runs  before  each  command  gets executed, or when the command
           changes state.  This is similar to postcmd,  but  it  does  not
           print builtins.

               > alias jobcmd  'echo -n "^[]2\;\!#:q^G"'

           then  executing  vi  foo.c  will  put the command string in the
           xterm title bar.

           Invoked by the run-help editor command.  The command  name  for
           which  help is sought is passed as sole argument.  For example,
           if one does

               > alias helpcommand '\!:1 --help'

           then the help display of the command itself  will  be  invoked,
           using  the  GNU help calling convention.  Currently there is no
           easy way to account for various calling conventions (e.g.,  the
           customary Unix `-h'), except by using a table of many commands.

           Runs  every  tperiod minutes.  This provides a convenient means
           for checking on common but infrequent changes such as new mail.
           For example, if one does

               > set tperiod = 30
               > alias periodic checknews

           then  the  checknews(1)  program  runs  every  30  minutes.  If
           periodic is set but tperiod is unset  or  set  to  0,  periodic
           behaves like precmd.

   precmd  Runs  just  before each prompt is printed.  For example, if one

               > alias precmd date

           then date(1) runs  just  before  the  shell  prompts  for  each
           command.   There are no limits on what precmd can be set to do,
           but discretion should be used.

   postcmd Runs before each command gets executed.

               > alias postcmd  'echo -n "^[]2\;\!#:q^G"'

           then executing vi foo.c will put  the  command  string  in  the
           xterm title bar.

   shell   Specifies  the  interpreter for executable scripts which do not
           themselves specify an interpreter.  The first word should be  a
           full  path name to the desired interpreter (e.g., `/bin/csh' or

   Special shell variables
   The variables described in this section have  special  meaning  to  the

   The  shell  sets  addsuffix,  argv,  autologout,  csubstnonl,  command,
   echo_style,  edit,  gid,  group,  home,  loginsh,  oid,  path,  prompt,
   prompt2,  prompt3, shell, shlvl, tcsh, term, tty, uid, user and version
   at startup; they do not change thereafter unless changed by  the  user.
   The  shell  updates  cwd,  dirstack, owd and status when necessary, and
   sets logout on logout.

   The shell synchronizes group, home, path, shlvl, term and user with the
   environment  variables  of  the  same  names:  whenever the environment
   variable changes the shell changes the corresponding shell variable  to
   match  (unless  the  shell variable is read-only) and vice versa.  Note
   that although cwd  and  PWD  have  identical  meanings,  they  are  not
   synchronized   in   this  manner,  and  that  the  shell  automatically
   interconverts the different formats of path and PATH.

   addsuffix (+)
           If set, filename completion adds `/' to the end of  directories
           and  a  space  to the end of normal files when they are matched
           exactly.  Set by default.

   afsuser (+)
           If set, autologout's autolock feature uses its value instead of
           the local username for kerberos authentication.

   ampm (+)
           If set, all times are shown in 12-hour AM/PM format.

   argv    The  arguments  to  the shell.  Positional parameters are taken
           from argv, i.e., `$1' is replaced by `$argv[1]', etc.   Set  by
           default, but usually empty in interactive shells.

   autocorrect (+)
           If  set, the spell-word editor command is invoked automatically
           before each completion attempt.

   autoexpand (+)
           If  set,  the  expand-history   editor   command   is   invoked
           automatically before each completion attempt. If this is set to
           onlyhistory, then only history will be expanded  and  a  second
           completion will expand filenames.

   autolist (+)
           If set, possibilities are listed after an ambiguous completion.
           If set to `ambiguous', possibilities are listed  only  when  no
           new characters are added by completion.

   autologout (+)
           The  first  word  is the number of minutes of inactivity before
           automatic logout.  The optional second word is  the  number  of
           minutes of inactivity before automatic locking.  When the shell
           automatically logs  out,  it  prints  `auto-logout',  sets  the
           variable  logout  to  `automatic'  and  exits.   When the shell
           automatically locks, the user is required to enter his password
           to   continue  working.   Five  incorrect  attempts  result  in
           automatic logout.  Set  to  `60'  (automatic  logout  after  60
           minutes,  and  no  locking)  by  default in login and superuser
           shells, but not if the shell  thinks  it  is  running  under  a
           window  system (i.e., the DISPLAY environment variable is set),
           the tty is a pseudo-tty (pty) or the shell was not so  compiled
           (see  the  version  shell  variable).  See also the afsuser and
           logout shell variables.

   autorehash (+)
           If set,  the  internal  hash  table  of  the  contents  of  the
           directories  in  the  path  variable  will  be  recomputed if a
           command is not found in the hash table.  In addition, the  list
           of   available  commands  will  be  rebuilt  for  each  command
           completion or spelling correction attempt if set to  `complete'
           or  `correct'  respectively;  if  set to `always', this will be
           done for both cases.

   backslash_quote (+)
           If set, backslashes (`\') always quote `\', `'', and `"'.  This
           may  make complex quoting tasks easier, but it can cause syntax
           errors in csh(1) scripts.

   catalog The file name  of  the  message  catalog.   If  set,  tcsh  use
           `tcsh.${catalog}'  as  a  message  catalog  instead  of default

   cdpath  A  list  of  directories  in  which  cd   should   search   for
           subdirectories if they aren't found in the current directory.

   color   If  set,  it  enables color display for the builtin ls-F and it
           passes --color=auto to ls.  Alternatively, it  can  be  set  to
           only  ls-F  or  only  ls  to  enable color to only one command.
           Setting it to nothing is equivalent to setting it to (ls-F ls).

           If set, it enables color escape sequence for NLS message files.
           And display colorful NLS messages.

   command (+)
           If  set,  the command which was passed to the shell with the -c
           flag (q.v.).

   compat_expr (+)
           If set, the shell will evaluate expressions right to left, like
           the original csh.

   complete (+)
           If  set  to `igncase', the completion becomes case insensitive.
           If set to `enhance',  completion  ignores  case  and  considers
           hyphens  and  underscores  to be equivalent; it will also treat
           periods, hyphens and underscores (`.', `-'  and  `_')  as  word
           separators.   If set to `Enhance', completion matches uppercase
           and underscore characters explicitly and matches lowercase  and
           hyphens  in  a  case-insensivite manner; it will treat periods,
           hypens and underscores as word separators.

   continue (+)
           If set to a list of  commands,  the  shell  will  continue  the
           listed commands, instead of starting a new one.

   continue_args (+)
           Same as continue, but the shell will execute:

               echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

   correct (+)
           If set to `cmd', commands are automatically spelling-corrected.
           If set to `complete', commands are automatically completed.  If
           set to `all', the entire command line is corrected.

   csubstnonl (+)
           If  set,  newlines and carriage returns in command substitution
           are replaced by spaces.  Set by default.

   cwd     The full pathname of  the  current  directory.   See  also  the
           dirstack and owd shell variables.

   dextract (+)
           If  set,  `pushd  +n'  extracts  the  nth  directory  from  the
           directory stack rather than rotating it to the top.

   dirsfile (+)
           The default location in which `dirs -S' and `dirs -L' look  for
           a  history  file.   If unset, ~/.cshdirs is used.  Because only
           ~/.tcshrc  is  normally  sourced  before  ~/.cshdirs,  dirsfile
           should be set in ~/.tcshrc rather than ~/.login.

   dirstack (+)
           An  array  of  all  the  directories  on  the  directory stack.
           `$dirstack[1]' is the current working directory, `$dirstack[2]'
           the  first  directory on the stack, etc.  Note that the current
           working directory is `$dirstack[1]' but `=0' in directory stack
           substitutions,  etc.   One  can change the stack arbitrarily by
           setting dirstack, but the first element  (the  current  working
           directory)  is  always correct.  See also the cwd and owd shell

   dspmbyte (+)
           Has an effect iff 'dspm' is listed as part of the version shell
           variable.  If set to `euc', it enables display and editing EUC-
           kanji(Japanese) code.  If set to `sjis', it enables display and
           editing Shift-JIS(Japanese) code.  If set to `big5', it enables
           display and editing Big5(Chinese) code.  If set to  `utf8',  it
           enables  display and editing Utf8(Unicode) code.  If set to the
           following format, it enables display and  editing  of  original
           multi-byte code format:

               > set dspmbyte = 0000....(256 bytes)....0000

           The  table  requires  just  256  bytes.   Each character of 256
           characters corresponds (from left to right) to the ASCII  codes
           0x00,  0x01,  ...  0xff.  Each character is set to number 0,1,2
           and 3.  Each number has the following meaning:
             0 ... not used for multi-byte characters.
             1 ... used for the first byte of a multi-byte character.
             2 ... used for the second byte of a multi-byte character.
             3 ... used for both the first  byte  and  second  byte  of  a
           multi-byte character.

           If  set  to  `001322',  the  first character (means 0x00 of the
           ASCII code) and second character (means 0x01 of ASCII code) are
           set  to  `0'.   Then, it is not used for multi-byte characters.
           The 3rd character (0x02) is set to '1', indicating that  it  is
           used  for  the  first  byte of a multi-byte character.  The 4th
           character(0x03) is set '3'.  It is used for both the first byte
           and the second byte of a multi-byte character.  The 5th and 6th
           characters (0x04,0x05) are set to '2', indicating that they are
           used for the second byte of a multi-byte character.

           The  GNU  fileutils  version  of  ls  cannot display multi-byte
           filenames without the -N ( --literal )  option.    If  you  are
           using  this  version,  set the second word of dspmbyte to "ls".
           If not,  for  example,  "ls-F  -l"  cannot  display  multi-byte

           This  variable  can only be used if KANJI and DSPMBYTE has been
           defined at compile time.

   dunique (+)
           If set, pushd removes any instances  of  name  from  the  stack
           before pushing it onto the stack.

   echo    If  set,  each command with its arguments is echoed just before
           it is executed.  For non-builtin commands all expansions  occur
           before echoing.  Builtin commands are echoed before command and
           filename substitution, because  these  substitutions  are  then
           done selectively.  Set by the -x command line option.

   echo_style (+)
           The style of the echo builtin.  May be set to

           bsd     Don't echo a newline if the first argument is `-n'.
           sysv    Recognize backslashed escape sequences in echo strings.
           both    Recognize  both  the  `-n'  flag and backslashed escape
                   sequences; the default.
           none    Recognize neither.

           Set by default to the local system default.  The BSD and System
           V  options  are  described  in  the  echo(1)  man  pages on the
           appropriate systems.

   edit (+)
           If set, the command-line editor is used.   Set  by  default  in
           interactive shells.

   ellipsis (+)
           If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
           shell variable) indicate skipped directories with  an  ellipsis
           (`...')  instead of `/<skipped>'.

   euid (+)
           The user's effective user ID.

   euser (+)
           The  first  matching  passwd  entry  name  corresponding to the
           effective user ID.

   fignore (+)
           Lists file name suffixes to be ignored by completion.

   filec   In tcsh, completion is always used and this variable is ignored
           by  default.  If  edit  is  unset,  then  the  traditional  csh
           completion is used.  If set  in  csh,  filename  completion  is

   gid (+) The user's real group ID.

   globdot (+)
           If   set,   wild-card   glob  patterns  will  match  files  and
           directories beginning with `.' except for `.' and `..'

   globstar (+)
           If set, the `**' and `***' file glob patterns  will  match  any
           string of characters including `/' traversing any existing sub-
           directories.  (e.g.  `ls **.c' will list all the  .c  files  in
           the  current directory tree).  If used by itself, it will match
           match    zero    or    more    sub-directories    (e.g.     `ls
           /usr/include/**/time.h'  will  list  any file named `time.h' in
           the    /usr/include     directory     tree;     whereas     `ls
           /usr/include/**time.h'  will match any file in the /usr/include
           directory tree ending in `time.h').  To prevent  problems  with
           recursion,  the  `**'  glob-pattern  will  not  descend  into a
           symbolic link containing a directory.  To  override  this,  use

   group (+)
           The user's group name.

           If  set,  the incremental search match (in i-search-back and i-
           search-fwd) and the region between the mark and the cursor  are
           highlighted in reverse video.

           Highlighting  requires  more  frequent  terminal  writes, which
           introduces  extra  overhead.  If  you   care   about   terminal
           performance, you may want to leave this unset.

           A  string  value  determining  the  characters  used in History
           substitution (q.v.).  The first character of its value is  used
           as  the  history  substitution character, replacing the default
           character `!'.  The second character of its value replaces  the
           character `^' in quick substitutions.

   histdup (+)
           Controls handling of duplicate entries in the history list.  If
           set to `all' only unique history  events  are  entered  in  the
           history  list.   If set to `prev' and the last history event is
           the same as the current command, then the  current  command  is
           not  entered  in  the  history.  If set to `erase' and the same
           event is found in the history list, that old event gets  erased
           and  the  current  one gets inserted.  Note that the `prev' and
           `all' options renumber history events so there are no gaps.

   histfile (+)
           The default location in which `history  -S'  and  `history  -L'
           look  for  a  history  file.   If  unset,  ~/.history  is used.
           histfile is useful when sharing the same home directory between
           different  machines,  or  when  saving  separate  histories  on
           different  terminals.   Because  only  ~/.tcshrc  is   normally
           sourced  before ~/.history, histfile should be set in ~/.tcshrc
           rather than ~/.login.

   histlit (+)
           If set, builtin and editor commands and the savehist  mechanism
           use the literal (unexpanded) form of lines in the history list.
           See also the toggle-literal-history editor command.

   history The first word indicates the number of history events to  save.
           The  optional  second  word  (+)  indicates the format in which
           history is printed; if not given, `%h\t%T\t%R\n' is used.   The
           format  sequences  are  described  below under prompt; note the
           variable meaning of `%R'.  Set to `100' by default.

   home    Initialized to the home directory of the invoker.  The filename
           expansion of `~' refers to this variable.

           If  set  to  the  empty string or `0' and the input device is a
           terminal, the end-of-file command  (usually  generated  by  the
           user by typing `^D' on an empty line) causes the shell to print
           `Use "exit" to leave tcsh.' instead of exiting.  This  prevents
           the  shell  from  accidentally being killed.  Historically this
           setting exited after 26  successive  EOF's  to  avoid  infinite
           loops.   If  set  to  a  number  n,  the  shell  ignores  n - 1
           consecutive end-of-files and exits on the nth.  (+)  If  unset,
           `1' is used, i.e., the shell exits on a single `^D'.

   implicitcd (+)
           If set, the shell treats a directory name typed as a command as
           though it were a request to change to that directory.   If  set
           to  verbose,  the change of directory is echoed to the standard
           output.  This behavior is inhibited  in  non-interactive  shell
           scripts,  or  for  command  strings  with  more  than one word.
           Changing directory takes precedence over executing a like-named
           command,  but  it is done after alias substitutions.  Tilde and
           variable expansions work as expected.

   inputmode (+)
           If set to `insert' or `overwrite', puts the  editor  into  that
           input mode at the beginning of each line.

   killdup (+)
           Controls  handling  of  duplicate entries in the kill ring.  If
           set to `all' only unique strings are entered in the kill  ring.
           If  set to `prev' and the last killed string is the same as the
           current killed string, then the current string is  not  entered
           in the ring.  If set to `erase' and the same string is found in
           the kill ring, the old string is erased and the current one  is

   killring (+)
           Indicates  the number of killed strings to keep in memory.  Set
           to `30' by default.  If unset or set  to  less  than  `2',  the
           shell  will only keep the most recently killed string.  Strings
           are put in the killring by  the  editor  commands  that  delete
           (kill)  strings  of text, e.g. backward-delete-word, kill-line,
           etc, as well as  the  copy-region-as-kill  command.   The  yank
           editor  command  will yank the most recently killed string into
           the command-line, while yank-pop (see Editor commands)  can  be
           used to yank earlier killed strings.

   listflags (+)
           If  set  to  `x', `a' or `A', or any combination thereof (e.g.,
           `xA'), they are used as flags to ls-F, making it act  like  `ls
           -xF',  `ls  -Fa',  `ls -FA' or a combination (e.g., `ls -FxA'):
           `a' shows all files (even if they start with a `.'), `A'  shows
           all  files  but  `.'  and `..', and `x' sorts across instead of
           down.  If the second word of listflags is set, it  is  used  as
           the path to `ls(1)'.

   listjobs (+)
           If set, all jobs are listed when a job is suspended.  If set to
           `long', the listing is in long format.

   listlinks (+)
           If set, the ls-F builtin command shows  the  type  of  file  to
           which each symbolic link points.

   listmax (+)
           The  maximum  number  of  items  which  the list-choices editor
           command will list without asking first.

   listmaxrows (+)
           The maximum number of rows  of  items  which  the  list-choices
           editor command will list without asking first.

   loginsh (+)
           Set  by the shell if it is a login shell.  Setting or unsetting
           it within a shell has no effect.  See also shlvl.

   logout (+)
           Set  by  the  shell  to  `normal'  before  a   normal   logout,
           `automatic'  before  an  automatic  logout, and `hangup' if the
           shell was killed by a hangup signal (see Signal handling).  See
           also the autologout shell variable.

   mail    A  list  of  files  and directories to check for incoming mail,
           optionally preceded by a numeric word.  Before each prompt,  if
           10  minutes  have passed since the last check, the shell checks
           each file and says `You have new mail.' (or, if  mail  contains
           multiple  files,  `You have new mail in name.') if the filesize
           is greater than zero  in  size  and  has  a  modification  time
           greater than its access time.

           If  you  are  in  a  login shell, then no mail file is reported
           unless it has been  modified  after  the  time  the  shell  has
           started  up,  to  prevent  redundant notifications.  Most login
           programs will tell you whether or not you have  mail  when  you
           log in.

           If  a  file  specified  in  mail is a directory, the shell will
           count each file within that directory as  a  separate  message,
           and  will  report  `You  have n mails.' or `You have n mails in
           name.'  as  appropriate.   This   functionality   is   provided
           primarily  for  those  systems which store mail in this manner,
           such as the Andrew Mail System.

           If the first word of mail is numeric it is taken as a different
           mail checking interval, in seconds.

           Under  very  rare circumstances, the shell may report `You have
           mail.' instead of `You have new mail.'

   matchbeep (+)
           If  set  to  `never',  completion  never  beeps.   If  set   to
           `nomatch',  it  beeps  only  when there is no match.  If set to
           `ambiguous', it beeps when there are multiple matches.  If  set
           to  `notunique',  it  beeps  when  there is one exact and other
           longer matches.  If unset, `ambiguous' is used.

   nobeep (+)
           If set, beeping is completely disabled.  See also visiblebell.

           If set, restrictions are placed on output redirection to insure
           that  files  are  not  accidentally  destroyed  and  that  `>>'
           redirections refer to  existing  files,  as  described  in  the
           Input/output section.

   noding  If  set,  disable  the  printing  of `DING!' in the prompt time
           specifiers at the change of hour.

   noglob  If set, Filename substitution and Directory stack  substitution
           (q.v.)  are  inhibited.   This  is most useful in shell scripts
           which do not deal with filenames, or after a list of  filenames
           has been obtained and further expansions are not desirable.

   nokanji (+)
           If  set  and  the  shell  supports Kanji (see the version shell
           variable), it is disabled so that the meta key can be used.

           If set, a Filename substitution or Directory stack substitution
           (q.v.)  which  does  not  match  any  existing  files  is  left
           untouched rather than causing an error.  It is still  an  error
           for  the  substitution  to  be  malformed, e.g., `echo [' still
           gives an error.

   nostat (+)
           A  list  of   directories   (or   glob-patterns   which   match
           directories;  see  Filename  substitution)  that  should not be
           stat(2)ed during a completion operation.  This is usually  used
           to exclude directories which take too much time to stat(2), for
           example /afs.

   notify  If set, the shell  announces  job  completions  asynchronously.
           The  default is to present job completions just before printing
           a prompt.

   oid (+) The user's real organization ID.  (Domain/OS only)

   owd (+) The old working directory, equivalent to the `-' used by cd and
           pushd.  See also the cwd and dirstack shell variables.

   padhour If set, enable the printing of padding '0' for hours, in 24 and
           12 hour formats.  E.G.: 07:45:42 vs. 7:45:42.

           To retain compatibily with  older  versions  numeric  variables
           starting  with  0  are  not  interpreted as octal. Setting this
           variable enables proper octal parsing.

   path    A list of directories in which to look for executable commands.
           A  null  word  specifies the current directory.  If there is no
           path variable then only full path names will execute.  path  is
           set  by the shell at startup from the PATH environment variable
           or, if PATH does  not  exist,  to  a  system-dependent  default
           something  like  `(/usr/local/bin  /usr/bsd  /bin /usr/bin .)'.
           The shell may put `.' first or last in path or omit it entirely
           depending  on  how  it  was  compiled;  see  the  version shell
           variable.  A shell which is given neither the  -c  nor  the  -t
           option  hashes  the  contents  of the directories in path after
           reading ~/.tcshrc and each time path is reset.  If one  adds  a
           new  command  to a directory in path while the shell is active,
           one may need to do a rehash for the shell to find it.

   printexitvalue (+)
           If set and an interactive program exits with a non-zero status,
           the shell prints `Exit status'.

   prompt  The  string  which  is printed before reading each command from
           the  terminal.   prompt  may  include  any  of  the   following
           formatting  sequences  (+),  which  are  replaced  by the given

           %/  The current working directory.
           %~  The  current  working  directory,  but  with   one's   home
               directory   represented   by  `~'  and  other  users'  home
               directories  represented  by  `~user'   as   per   Filename
               substitution.   `~user'  substitution  happens  only if the
               shell has already used `~user' in a pathname in the current
           %c[[0]n], %.[[0]n]
               The trailing component of the current working directory, or
               n trailing components if a digit n is given.  If  n  begins
               with  `0',  the  number  of  skipped components precede the
               trailing component(s) in the  format  `/<skipped>trailing'.
               If  the  ellipsis shell variable is set, skipped components
               are  represented  by  an  ellipsis  so  the  whole  becomes
               `...trailing'.   `~' substitution is done as in `%~' above,
               but the `~' component is  ignored  when  counting  trailing
           %C  Like %c, but without `~' substitution.
           %h, %!, !
               The current history event number.
           %M  The full hostname.
           %m  The hostname up to the first `.'.
           %S (%s)
               Start (stop) standout mode.
           %B (%b)
               Start (stop) boldfacing mode.
           %U (%u)
               Start (stop) underline mode.
           %t, %@
               The time of day in 12-hour AM/PM format.
           %T  Like  `%t',  but  in 24-hour format (but see the ampm shell
           %p  The `precise' time of day in  12-hour  AM/PM  format,  with
           %P  Like  `%p',  but  in 24-hour format (but see the ampm shell
           \c  c is parsed as in bindkey.
           ^c  c is parsed as in bindkey.
           %%  A single `%'.
           %n  The user name.
           %N  The effective user name.
           %j  The number of jobs.
           %d  The weekday in `Day' format.
           %D  The day in `dd' format.
           %w  The month in `Mon' format.
           %W  The month in `mm' format.
           %y  The year in `yy' format.
           %Y  The year in `yyyy' format.
           %l  The shell's tty.
           %L  Clears from the end of the prompt to end of the display  or
               the end of the line.
           %$  Expands  the shell or environment variable name immediately
               after the `$'.
           %#  `>' (or  the  first  character  of  the  promptchars  shell
               variable) for normal users, `#' (or the second character of
               promptchars) for the superuser.
               Includes string as a literal escape sequence.  It should be
               used only to change terminal attributes and should not move
               the cursor location.  This cannot be the last  sequence  in
           %?  The  return  code  of  the command executed just before the
           %R  In prompt2, the status of  the  parser.   In  prompt3,  the
               corrected string.  In history, the history string.

           `%B',  `%S', `%U' and `%{string%}' are available in only eight-
           bit-clean shells; see the version shell variable.

           The bold, standout and underline sequences are  often  used  to
           distinguish a superuser shell.  For example,

               > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
               tut [37] [2:54pm] [/usr/accts/sys] you rang? _

           If  `%t',  `%@', `%T', `%p', or `%P' is used, and noding is not
           set, then print `DING!' on  the  change  of  hour  (i.e,  `:00'
           minutes) instead of the actual time.

           Set by default to `%# ' in interactive shells.

   prompt2 (+)
           The  string with which to prompt in while and foreach loops and
           after lines ending in `\'.  The same format  sequences  may  be
           used  as  in  prompt (q.v.); note the variable meaning of `%R'.
           Set by default to `%R? ' in interactive shells.

   prompt3 (+)
           The string with  which  to  prompt  when  confirming  automatic
           spelling  correction.  The same format sequences may be used as
           in prompt (q.v.); note the variable meaning of  `%R'.   Set  by
           default to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

   promptchars (+)
           If  set  (to  a  two-character  string),  the  `%#'  formatting
           sequence in the prompt shell  variable  is  replaced  with  the
           first  character  for normal users and the second character for
           the superuser.

   pushdtohome (+)
           If set, pushd without arguments does `pushd ~', like cd.

   pushdsilent (+)
           If set, pushd and popd do not print the directory stack.

   recexact (+)
           If set, completion completes on an exact match even if a longer
           match is possible.

   recognize_only_executables (+)
           If  set,  command  listing displays only files in the path that
           are executable.  Slow.

   rmstar (+)
           If set, the user is prompted before `rm *' is executed.

   rprompt (+)
           The string to print on the right-hand side of the screen (after
           the  command  input)  when the prompt is being displayed on the
           left.  It recognizes the same formatting characters as  prompt.
           It  will  automatically disappear and reappear as necessary, to
           ensure that command input isn't obscured, and will appear  only
           if  the  prompt, command input, and itself will fit together on
           the first line.  If  edit  isn't  set,  then  rprompt  will  be
           printed after the prompt and before the command input.

   savedirs (+)
           If  set, the shell does `dirs -S' before exiting.  If the first
           word is set to a number, at  most  that  many  directory  stack
           entries are saved.

           If  set,  the  shell  does `history -S' before exiting.  If the
           first word is set to a number, at  most  that  many  lines  are
           saved.  (The number must be less than or equal to history.)  If
           the second word is set to `merge', the history list  is  merged
           with  the  existing  history  file  instead of replacing it (if
           there is one) and sorted by time  stamp  and  the  most  recent
           events are retained.  (+)

   sched (+)
           The  format in which the sched builtin command prints scheduled
           events; if not  given,  `%h\t%T\t%R\n'  is  used.   The  format
           sequences  are  described above under prompt; note the variable
           meaning of `%R'.

   shell   The file in which the shell resides.  This is used  in  forking
           shells  to  interpret  files  which  have execute bits set, but
           which are not executable by the system.  (See  the  description
           of  Builtin and non-builtin command execution.)  Initialized to
           the (system-dependent) home of the shell.

   shlvl (+)
           The number of nested shells.  Reset to 1 in login shells.   See
           also loginsh.

   status  The  status  returned  by the last command, unless the variable
           anyerror is set, and any error in a  pipeline  or  a  backquote
           expansion will be propagated (this is the default csh behavior,
           and the current tcsh default).  If  it  terminated  abnormally,
           then  0200 is added to the status.  Builtin commands which fail
           return exit status  `1',  all  other  builtin  commands  return
           status `0'.

   symlinks (+)
           Can be set to several different values to control symbolic link
           (`symlink') resolution:

           If set to `chase', whenever the current directory changes to  a
           directory  containing  a  symbolic  link, it is expanded to the
           real name of the directory to which the link points.  This does
           not work for the user's home directory; this is a bug.

           If  set  to  `ignore',  the  shell tries to construct a current
           directory relative to the current directory before the link was
           crossed.   This  means  that  cding through a symbolic link and
           then `cd ..'ing returns one to the  original  directory.   This
           affects only builtin commands and filename completion.

           If  set  to  `expand', the shell tries to fix symbolic links by
           actually expanding arguments which look like path names.   This
           affects  any  command,  not just builtins.  Unfortunately, this
           does not work for hard-to-recognize filenames,  such  as  those
           embedded  in  command  options.   Expansion may be prevented by
           quoting.  While this setting is usually the most convenient, it
           is  sometimes  misleading and sometimes confusing when it fails
           to  recognize  an  argument  which  should  be   expanded.    A
           compromise  is  to  use  `ignore'  and  use  the editor command
           normalize-path (bound by default to ^X-n) when necessary.

           Some examples are in order.  First,  let's  set  up  some  play

               > cd /tmp
               > mkdir from from/src to
               > ln -s from/src to/dst

           Here's the behavior with symlinks unset,

               > cd /tmp/to/dst; echo $cwd
               > cd ..; echo $cwd

           here's the behavior with symlinks set to `chase',

               > cd /tmp/to/dst; echo $cwd
               > cd ..; echo $cwd

           here's the behavior with symlinks set to `ignore',

               > cd /tmp/to/dst; echo $cwd
               > cd ..; echo $cwd

           and here's the behavior with symlinks set to `expand'.

               > cd /tmp/to/dst; echo $cwd
               > cd ..; echo $cwd
               > cd /tmp/to/dst; echo $cwd
               > cd ".."; echo $cwd
               > /bin/echo ..
               > /bin/echo ".."

           Note  that  `expand'  expansion 1) works just like `ignore' for
           builtins like cd, 2) is prevented by quoting,  and  3)  happens
           before filenames are passed to non-builtin commands.

   tcsh (+)
           The  version number of the shell in the format `R.VV.PP', where
           `R' is the major release number, `VV' the current  version  and
           `PP' the patchlevel.

   term    The  terminal type.  Usually set in ~/.login as described under
           Startup and shutdown.

   time    If set to a number,  then  the  time  builtin  (q.v.)  executes
           automatically  after  each  command  which takes more than that
           many CPU seconds.  If there is a second word, it is used  as  a
           format  string  for  the  output  of the time builtin.  (u) The
           following sequences may be used in the format string:

           %U  The time the process spent in user mode in cpu seconds.
           %S  The time the process spent in kernel mode in cpu seconds.
           %E  The elapsed (wall clock) time in seconds.
           %P  The CPU percentage computed as (%U + %S) / %E.
           %W  Number of times the process was swapped.
           %X  The average amount in (shared) text space used in Kbytes.
           %D  The average amount in (unshared) data/stack space  used  in
           %K  The total space used (%X + %D) in Kbytes.
           %M  The  maximum  memory  the process had in use at any time in
           %F  The number of major page faults (page needed to be  brought
               from disk).
           %R  The number of minor page faults.
           %I  The number of input operations.
           %O  The number of output operations.
           %r  The number of socket messages received.
           %s  The number of socket messages sent.
           %k  The number of signals received.
           %w  The number of voluntary context switches (waits).
           %c  The number of involuntary context switches.

           Only  the first four sequences are supported on systems without
           BSD resource limit functions.  The default time format is  `%Uu
           %Ss  %E  %P  %X+%Dk  %I+%Oio %Fpf+%Ww' for systems that support
           resource usage reporting and `%Uu %Ss %E %P' for  systems  that
           do not.

           Under  Sequent's  DYNIX/ptx,  %X,  %D,  %K,  %r  and %s are not
           available, but the following additional sequences are:

           %Y  The number of system calls performed.
           %Z  The number of pages which are zero-filled on demand.
           %i  The number of times  a  process's  resident  set  size  was
               increased by the kernel.
           %d  The  number  of  times  a  process's  resident set size was
               decreased by the kernel.
           %l  The number of read system calls performed.
           %m  The number of write system calls performed.
           %p  The number of reads from raw disk devices.
           %q  The number of writes to raw disk devices.

           and  the  default  time  format  is  `%Uu  %Ss  %E  %P  %I+%Oio
           %Fpf+%Ww'.   Note  that  the  CPU percentage can be higher than
           100% on multi-processors.

   tperiod (+)
           The period, in minutes,  between  executions  of  the  periodic
           special alias.

   tty (+) The name of the tty, or empty if not attached to one.

   uid (+) The user's real user ID.

   user    The user's login name.

   verbose If  set,  causes the words of each command to be printed, after
           history substitution (if any).  Set  by  the  -v  command  line

   version (+)
           The  version  ID stamp.  It contains the shell's version number
           (see tcsh), origin, release date, vendor, operating system  and
           machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
           list of options which were set at compile time.  Options  which
           are set by default in the distribution are noted.

           8b    The shell is eight bit clean; default
           7b    The shell is not eight bit clean
           wide  The shell is multibyte encoding clean (like UTF-8)
           nls   The system's NLS is used; default for systems with NLS
           lf    Login  shells  execute  /etc/csh.login  before instead of
                 after /etc/csh.cshrc and ~/.login before instead of after
                 ~/.tcshrc and ~/.history.
           dl    `.' is put last in path for security; default
           nd    `.' is omitted from path for security
           vi    vi-style editing is the default rather than emacs
           dtr   Login shells drop DTR when exiting
           bye   bye  is a synonym for logout and log is an alternate name
                 for watchlog
           al    autologout is enabled; default
           kan   Kanji  is  used  if  appropriate  according   to   locale
                 settings, unless the nokanji shell variable is set
           sm    The system's malloc(3) is used
           hb    The  `#!<program>  <args>'  convention  is  emulated when
                 executing shell scripts
           ng    The newgrp builtin is available
           rh    The shell attempts  to  set  the  REMOTEHOST  environment
           afs   The shell verifies your password with the kerberos server
                 if  local  authentication  fails.   The   afsuser   shell
                 variable  or  the  AFSUSER  environment variable override
                 your local username if set.

           An administrator  may  enter  additional  strings  to  indicate
           differences in the local version.

   visiblebell (+)
           If  set,  a  screen flash is used rather than the audible bell.
           See also nobeep.

   watch (+)
           A list of user/terminal pairs to watch for logins and  logouts.
           If  either  the user is `any' all terminals are watched for the
           given user and  vice  versa.   Setting  watch  to  `(any  any)'
           watches all users and terminals.  For example,

               set watch = (george ttyd1 any console $user any)

           reports activity of the user `george' on ttyd1, any user on the
           console, and oneself (or a trespasser) on any terminal.

           Logins and logouts are checked every 10 minutes by default, but
           the  first  word of watch can be set to a number to check every
           so many minutes.  For example,

               set watch = (1 any any)

           reports any login/logout once every minute.  For the impatient,
           the  log  builtin  command triggers a watch report at any time.
           All current logins are reported (as with the log builtin)  when
           watch is first set.

           The who shell variable controls the format of watch reports.

   who (+) The  format string for watch messages.  The following sequences
           are replaced by the given information:

           %n  The name of the user who logged in/out.
           %a  The observed action, i.e., `logged  on',  `logged  off'  or
               `replaced olduser on'.
           %l  The terminal (tty) on which the user logged in/out.
           %M  The  full  hostname  of  the remote host, or `local' if the
               login/logout was from the local host.
           %m  The hostname of the remote host up to the first  `.'.   The
               full  name is printed if it is an IP address or an X Window
               System display.

           %M and %m are available on only systems that store  the  remote
           hostname  in  /etc/utmp.   If unset, `%n has %a %l from %m.' is
           used, or `%n has %a %l.'  on  systems  which  don't  store  the
           remote hostname.

   wordchars (+)
           A  list of non-alphanumeric characters to be considered part of
           a  word  by  the  forward-word,  backward-word   etc.,   editor
           commands.  If unset, `*?_-.[]~=' is used.


   AFSUSER (+)
           Equivalent to the afsuser shell variable.

   COLUMNS The   number   of   columns  in  the  terminal.   See  Terminal

   DISPLAY Used by X Window System (see X(1)).  If set, the shell does not
           set autologout (q.v.).

   EDITOR  The  pathname  to  a  default  editor.   See  also  the  VISUAL
           environment variable and the run-fg-editor editor command.

   GROUP (+)
           Equivalent to the group shell variable.

   HOME    Equivalent to the home shell variable.

   HOST (+)
           Initialized to the name of the machine on which  the  shell  is
           running, as determined by the gethostname(2) system call.

           Initialized  to  the  type  of  machine  on  which the shell is
           running, as determined  at  compile  time.   This  variable  is
           obsolete and will be removed in a future version.

   HPATH (+)
           A  colon-separated  list  of  directories in which the run-help
           editor command looks for command documentation.

   LANG    Gives the preferred character environment.  See Native Language
           System support.

           If  set,  only ctype character handling is changed.  See Native
           Language System support.

   LINES   The number of lines in the terminal.  See Terminal management.

           The format of this variable is reminiscent  of  the  termcap(5)
           file  format; a colon-separated list of expressions of the form
           "xx=string", where "xx" is a two-character variable name.   The
           variables with their associated defaults are:

               no   0      Normal (non-filename) text
               fi   0      Regular file
               di   01;34  Directory
               ln   01;36  Symbolic link
               pi   33     Named pipe (FIFO)
               so   01;35  Socket
               do   01;35  Door
               bd   01;33  Block device
               cd   01;32  Character device
               ex   01;32  Executable file
               mi   (none) Missing file (defaults to fi)
               or   (none) Orphaned symbolic link (defaults to ln)
               lc   ^[[    Left code
               rc   m      Right code
               ec   (none) End code (replaces lc+no+rc)

           You  need to include only the variables you want to change from
           the default.

           File names can also be colorized based on  filename  extension.
           This  is  specified  in the LS_COLORS variable using the syntax
           "*ext=string".  For example, using ISO 6429 codes, to color all
           C-language  source files blue you would specify "*.c=34".  This
           would color all files ending in .c in blue (34) color.

           Control characters can be  written  either  in  C-style-escaped
           notation,  or  in  stty-like  ^-notation.  The C-style notation
           adds ^[ for Escape, _ for a normal space character, and  ?  for
           Delete.   In  addition,  the ^[ escape character can be used to
           override the default interpretation of ^[, ^, : and =.

           Each file will be written as <lc> <color-code> <rc>  <filename>
           <ec>.   If  the  <ec> code is undefined, the sequence <lc> <no>
           <rc> will be used instead.  This is generally  more  convenient
           to  use,  but  less general.  The left, right and end codes are
           provided so you don't have to type common parts over  and  over
           again  and  to  support weird terminals; you will generally not
           need to change them at all unless your terminal  does  not  use
           ISO 6429 color sequences but a different system.

           If your terminal does use ISO 6429 color codes, you can compose
           the type codes (i.e., all except the lc, rc, and ec codes) from
           numerical  commands  separated  by semicolons.  The most common
           commands are:

                   0   to restore default color
                   1   for brighter colors
                   4   for underlined text
                   5   for flashing text
                   30  for black foreground
                   31  for red foreground
                   32  for green foreground
                   33  for yellow (or brown) foreground
                   34  for blue foreground
                   35  for purple foreground
                   36  for cyan foreground
                   37  for white (or gray) foreground
                   40  for black background
                   41  for red background
                   42  for green background
                   43  for yellow (or brown) background
                   44  for blue background
                   45  for purple background
                   46  for cyan background
                   47  for white (or gray) background

           Not all commands will work on all systems or display devices.

           A few terminal programs do not recognize the default  end  code
           properly.   If all text gets colorized after you do a directory
           listing, try changing the  no  and  fi  codes  from  0  to  the
           numerical codes for your standard fore- and background colors.

           The  machine  type  (microprocessor class or machine model), as
           determined at compile time.

           If set, printable characters are not  rebound  to  self-insert-
           command.  See Native Language System support.

   OSTYPE (+)
           The operating system, as determined at compile time.

   PATH    A  colon-separated  list  of  directories  in which to look for
           executables.  Equivalent to the path shell variable, but  in  a
           different format.

   PWD (+) Equivalent  to  the cwd shell variable, but not synchronized to
           it; updated only after an actual directory change.

           The host from which the user has logged in remotely, if this is
           the  case  and  the shell is able to determine it.  Set only if
           the shell was so compiled; see the version shell variable.

   SHLVL (+)
           Equivalent to the shlvl shell variable.

   SYSTYPE (+)
           The current system type.  (Domain/OS only)

   TERM    Equivalent to the term shell variable.

   TERMCAP The terminal capability string.  See Terminal management.

   USER    Equivalent to the user shell variable.

   VENDOR (+)
           The vendor, as determined at compile time.

   VISUAL  The pathname to a default full-screen  editor.   See  also  the
           EDITOR   environment  variable  and  the  run-fg-editor  editor


   /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and Intel
                   use  /etc/cshrc  and  NeXTs  use /etc/cshrc.std.  A/UX,
                   AMIX, Cray and IRIX have no equivalent in  csh(1),  but
                   read  this  file  in tcsh anyway.  Solaris 2.x does not
                   have it either, but tcsh reads /etc/.cshrc.  (+)
   /etc/csh.login  Read by login shells after  /etc/csh.cshrc.   ConvexOS,
                   Stellix   and   Intel   use   /etc/login,   NeXTs   use
                   /etc/login.std, Solaris 2.x uses /etc/.login and  A/UX,
                   AMIX, Cray and IRIX use /etc/cshrc.
   ~/.tcshrc (+)   Read   by  every  shell  after  /etc/csh.cshrc  or  its
   ~/.cshrc        Read by every shell, if ~/.tcshrc doesn't exist,  after
                   /etc/csh.cshrc  or  its  equivalent.   This manual uses
                   `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is  not
                   found, ~/.cshrc'.
   ~/.history      Read  by  login  shells  after ~/.tcshrc if savehist is
                   set, but see also histfile.
   ~/.login        Read by login shells  after  ~/.tcshrc  or  ~/.history.
                   The  shell  may  be  compiled  to  read ~/.login before
                   instead of after  ~/.tcshrc  and  ~/.history;  see  the
                   version shell variable.
   ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is set,
                   but see also dirsfile.
   /etc/csh.logout Read by login shells at logout.  ConvexOS, Stellix  and
                   Intel  use  /etc/logout  and NeXTs use /etc/logout.std.
                   A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
                   but  read  this  file in tcsh anyway.  Solaris 2.x does
                   not have it either, but tcsh reads /etc/.logout.  (+)
   ~/.logout       Read by login shells at logout after /etc/csh.logout or
                   its equivalent.
   /bin/sh         Used  to  interpret  shell  scripts not starting with a
   /tmp/sh*        Temporary file for `<<'.
   /etc/passwd     Source of home directories for `~name' substitutions.

   The order in which startup files are read may differ if the  shell  was
   so compiled; see Startup and shutdown and the version shell variable.


   This  manual  describes tcsh as a single entity, but experienced csh(1)
   users will want to pay special attention to tcsh's new features.

   A command-line editor, which supports  GNU  Emacs  or  vi(1)-style  key
   bindings.  See The command-line editor and Editor commands.

   Programmable,  interactive word completion and listing.  See Completion
   and listing and the complete and uncomplete builtin commands.

   Spelling correction (q.v.) of filenames, commands and variables.

   Editor commands (q.v.) which perform  other  useful  functions  in  the
   middle  of  typed  commands, including documentation lookup (run-help),
   quick editor restarting (run-fg-editor) and command resolution  (which-

   An  enhanced  history  mechanism.  Events in the history list are time-
   stamped.  See  also  the  history  command  and  its  associated  shell
   variables,  the  previously  undocumented  `#'  event specifier and new
   modifiers under History substitution, the *-history,  history-search-*,
   i-search-*,  vi-search-* and toggle-literal-history editor commands and
   the histlit shell variable.

   Enhanced directory parsing and directory stack handling.  See  the  cd,
   pushd, popd and dirs commands and their associated shell variables, the
   description of Directory stack  substitution,  the  dirstack,  owd  and
   symlinks  shell  variables and the normalize-command and normalize-path
   editor commands.

   Negation in glob-patterns.  See Filename substitution.

   New File inquiry operators (q.v.) and a  filetest  builtin  which  uses

   A  variety  of  Automatic,  periodic  and timed events (q.v.) including
   scheduled  events,  special  aliases,  automatic  logout  and  terminal
   locking, command timing and watching for logins and logouts.

   Support  for  the  Native  Language  System (see Native Language System
   support),  OS  variant  features  (see  OS  variant  support  and   the
   echo_style  shell  variable)  and  system-dependent file locations (see

   Extensive terminal-management capabilities.  See Terminal management.

   New builtin commands including builtins, hup, ls-F,  newgrp,  printenv,
   which and where (q.v.).

   New  variables  that  make  useful  information easily available to the
   shell.  See the gid, loginsh, oid, shlvl, tcsh, tty,  uid  and  version
   shell  variables  and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
   environment variables.

   A new syntax for including useful information in the prompt string (see
   prompt),  and  special  prompts  for loops and spelling correction (see
   prompt2 and prompt3).

   Read-only variables.  See Variable substitution.


   When a suspended command is restarted, the shell prints  the  directory
   it  started  in  if this is different from the current directory.  This
   can be misleading (i.e., wrong) as the job may have changed directories

   Shell   builtin   functions  are  not  stoppable/restartable.   Command
   sequences of the form `a ; b ; c' are also not handled gracefully  when
   stopping  is  attempted.   If  you  suspend  `b',  the  shell will then
   immediately  execute  `c'.   This  is  especially  noticeable  if  this
   expansion  results from an alias.  It suffices to place the sequence of
   commands in ()'s to force it to a subshell, i.e., `( a ; b ; c )'.

   Control over tty output  after  processes  are  started  is  primitive;
   perhaps  this  will  inspire someone to work on a good virtual terminal
   interface.  In a  virtual  terminal  interface  much  more  interesting
   things could be done with output control.

   Alias  substitution  is  most  often  used  to  clumsily simulate shell
   procedures; shell procedures should be provided rather than aliases.

   Control structures should be parsed rather  than  being  recognized  as
   built-in  commands.   This  would  allow  control commands to be placed
   anywhere, to be combined with `|', and to be  used  with  `&'  and  `;'

   foreach doesn't ignore here documents when looking for its end.

   It should be possible to use the `:' modifiers on the output of command

   The screen update for lines longer than the screen width is  very  poor
   if the terminal cannot move the cursor up (i.e., terminal type `dumb').

   HPATH and NOREBIND don't need to be environment variables.

   Glob-patterns  which  do  not use `?', `*' or `[]' or which use `{}' or
   `~' are not negated correctly.

   The single-command form of if  does  output  redirection  even  if  the
   expression is false and the command is not executed.

   ls-F includes file identification characters when sorting filenames and
   does not handle control characters in filenames  well.   It  cannot  be

   Command substitution supports multiple commands and conditions, but not
   cycles or backward gotos.

   Report bugs at, preferably with fixes.  If you want
   to  help  maintain  and  test tcsh, send mail to
   with the text `subscribe tcsh' on a line by itself in the body.


   In  1964,  DEC  produced  the  PDP-6.   The  PDP-10  was  a  later  re-
   implementation.   It  was  re-christened the DECsystem-10 in 1970 or so
   when DEC brought out the second model, the KI10.

   TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
   think  tank)  in  1972  as an experiment in demand-paged virtual memory
   operating systems.  They built a new  pager  for  the  DEC  PDP-10  and
   created the OS to go with it.  It was extremely successful in academia.

   In  1975,  DEC  brought  out  a new model of the PDP-10, the KL10; they
   intended to have only a version of TENEX, which they had licensed  from
   BBN,  for  the  new  box.   They  called  their  version TOPS-20 (their
   capitalization is trademarked).  A lot of TOPS-10 users (`The OPerating
   System  for PDP-10') objected; thus DEC found themselves supporting two
   incompatible systems on the same hardware--but then there were 6 on the

   TENEX,  and  TOPS-20  to  version 3, had command completion via a user-
   code-level subroutine library called ULTCMD.  With version 3, DEC moved
   all  that  capability  and more into the monitor (`kernel' for you Unix
   types), accessed by the COMND% JSYS (`Jump to SYStem' instruction,  the
   supervisor call mechanism [are my IBM roots also showing?]).

   The creator of tcsh was impressed by this feature and several others of
   TENEX and TOPS-20, and created a version of csh which mimicked them.


   The system limits argument lists to ARG_MAX characters.

   The number of arguments to a command which involves filename  expansion
   is  limited  to  1/6th  the number of characters allowed in an argument

   Command substitutions  may  substitute  no  more  characters  than  are
   allowed in an argument list.

   To   detect   looping,   the   shell  restricts  the  number  of  alias
   substitutions on a single line to 20.


   csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1),  su(1),
   tset(1),   vi(1),   x(1),  access(2),  execve(2),  fork(2),  killpg(2),
   pipe(2), setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2),
   malloc(3),  setlocale(3),  tty(4),  a.out(5),  termcap(5),  environ(7),
   termio(7), Introduction to the C Shell


   This manual documents tcsh 6.18.01 (Astron) 2012-02-14.


   William Joy
     Original author of csh(1)
   J.E. Kulp, IIASA, Laxenburg, Austria
     Job control and directory stack features
   Ken Greer, HP Labs, 1981
     File name completion
   Mike Ellis, Fairchild, 1983
     Command name recognition/completion
   Paul Placeway, Ohio State CIS Dept., 1983-1993
     Command line editor, prompt routines, new glob  syntax  and  numerous
     fixes and speedups
   Karl Kleinpaste, CCI 1983-4
     Special  aliases,  directory  stack  extraction  stuff,  login/logout
     watch, scheduled events, and the idea of the new prompt format
   Rayan Zachariassen, University of Toronto, 1984
     ls-F and which builtins and numerous  bug  fixes,  modifications  and
   Chris Kingsley, Caltech
     Fast storage allocator routines
   Chris Grevstad, TRW, 1987
     Incorporated 4.3BSD csh into tcsh
   Christos S. Zoulas, Cornell U. EE Dept., 1987-94
     Ports   to   HPUX,   SVR2  and  SVR3,  a  SysV  version  of  getwd.c,
     SHORT_STRINGS support and a new version of sh.glob.c
   James J Dempsey, BBN, and Paul Placeway, OSU, 1988
     A/UX port
   Daniel Long, NNSC, 1988
   Patrick Wolfe, Kuck and Associates, Inc., 1988
     vi mode cleanup
   David C Lawrence, Rensselaer Polytechnic Institute, 1989
     autolist and ambiguous completion listing
   Alec Wolman, DEC, 1989
     Newlines in the prompt
   Matt Landau, BBN, 1989
   Ray Moody, Purdue Physics, 1989
     Magic space bar history expansion
   Mordechai ????, Intel, 1989
     printprompt() fixes and additions
   Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
     Automatic spelling correction and prompt3
   Per Hedeland, Ellemtel, Sweden, 1990-
     Various bugfixes, improvements and manual updates
   Hans J. Albertsson (Sun Sweden)
     ampm, settc and telltc
   Michael Bloom
     Interrupt handling fixes
   Michael Fine, Digital Equipment Corp
     Extended key support
   Eric Schnoebelen, Convex, 1990
     Convex support, lots of csh bug fixes, save and restore of  directory
   Ron Flax, Apple, 1990
     A/UX 2.0 (re)port
   Dan Oscarsson, LTH Sweden, 1990
     NLS support and simulated NLS support for non NLS sites, fixes
   Johan Widen, SICS Sweden, 1990
     shlvl, Mach support, correct-line, 8-bit printing
   Matt Day, Sanyo Icon, 1990
     POSIX termio support, SysV limit fixes
   Jaap Vermeulen, Sequent, 1990-91
     Vi mode fixes, expand-line, window change fixes, Symmetry port
   Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
     autolist  beeping  options, modified the history search to search for
     the whole string from the beginning of the line to the cursor.
   Scott Krotz, Motorola, 1991
     Minix port
   David Dawes, Sydney U. Australia, Physics Dept., 1991
     SVR4 job control fixes
   Jose Sousa, Interactive Systems Corp., 1991
     Extended vi fixes and vi delete command
   Marc Horowitz, MIT, 1991
     ANSIfication fixes, new exec hashing code, imake fixes, where
   Bruce Sterling Woodcock,, 1991-1995
     ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n  addition,
     and various other portability changes and bug fixes
   Jeff Fink, 1992
     complete-word-fwd and complete-word-back
   Harry C. Pulley, 1992
     Coherent port
   Andy Phillips, Mullard Space Science Lab U.K., 1992
     VMS-POSIX port
   Beto Appleton, IBM Corp., 1992
     Walking  process  group fixes, csh bug fixes, POSIX file tests, POSIX
   Scott Bolte, Cray Computer Corp., 1992
     CSOS port
   Kaveh R. Ghazi, Rutgers University, 1992
     Tek, m88k, Titan  and  Masscomp  ports  and  fixes.   Added  autoconf
   Mark Linderman, Cornell University, 1992
     OS/2 port
   Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
     Linux port
   Tim P. Starrin, NASA Langley Research Center Operations, 1993
     Read-only variables
   Dave Schweisguth, Yale University, 1993-4
     New man page and tcsh.man2html
   Larry Schwimmer, Stanford University, 1993
     AFS and HESIOD patches
   Luke Mewburn, RMIT University, 1994-6
     Enhanced directory printing in prompt, added ellipsis and rprompt.
   Edward Hutchins, Silicon Graphics Inc., 1996
     Added implicit cd.
   Martin Kraemer, 1997
     Ported to Siemens Nixdorf EBCDIC machine
   Amol Deshpande, Microsoft, 1997
     Ported  to  WIN32  (Windows/95 and Windows/NT); wrote all the missing
     library and message catalog code to interface to Windows.
   Taga Nayuta, 1998
     Color ls additions.


   Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
   Diana  Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
   the other people at Ohio State for suggestions and encouragement

   All the people on the net, for putting up with, reporting bugs in,  and
   suggesting new additions to each and every version

   Richard M. Alderson III, for writing the `T in tcsh' section


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