gpm(8)


NAME

   gpm - a cut and paste utility and mouse server for virtual consoles

SYNOPSIS

   gpm [ options ]

DESCRIPTION

   This package tries to be a useful mouse server for applications running
   on the Linux console.  It is based on the "selection" package, and some
   of  its code comes from selection itself. This package is intended as a
   replacement for "selection"  as  a  cut-and-paste  mechanism;  it  also
   provides  additional  facilities.  The  "selection" package offered the
   first cut-and-paste implementation for Linux using two  mouse  buttons,
   and  the  cut  buffer  is  still  called  "selection  buffer"  or  just
   "selection"  throughout  this  document.   The  information  below   is
   extracted  from  the  texinfo  file,  which  is the preferred source of
   information.

   The `gpm' executable is meant to act like a daemon (thus, `gpmd'  would
   be  a  better  name  for  it).  This  section  is meant to describe the
   command-line options for `gpm', while its internals are outlined in the
   next section.

   Due  to  restrictions in the `ioctl(TIOCLINUX)' system call, `gpm' must
   be run by the superuser. The restrictions have been added in  the  last
   1.1  kernels  to  fix  a  security hole related to selection and screen
   dumping.

   The server can be  configured  to  match  the  user's  taste,  and  any
   application  using  the  mouse will inherit the server's attitude. From
   release 1.02 up to 1.19.2 is was possible for any user  logged  on  the
   system console to change the mouse feeling using the -q option. This is
   no longer possible for security reasons.

   As of 0.97 the server program puts itself in the  background.  To  kill
   `gpm'  you  can just reinvoke it with the `-k' cmdline switch, although
   `killall gpm' can be a better choice.

SPECIAL COMMANDS

   Version 1.10 adds the capability to execute special commands on certain
   circumstances.  Special  commands  default to rebooting and halting the
   system,  but  the  user  can  specify  his/her  personal  choice.   The
   capability  to  invoke  commands  using  the  mouse  is a handy one for
   programmers, because it allows to  issue  a  clean  shutdown  when  the
   keyboard is locked and no network is available to restore the system to
   a sane state.

   Special commands are toggled by  triple-clicking  the  left  and  right
   button  -- an unlikely event during normal mouse usage. The easiest way
   to triple-click is pressing one of the  buttons  and  triple-click  the
   other one. When special processing is toggled, a message appears on the
   console (and the speaker beeps twice, if you have a  speaker);  if  the
   user  releases  all  the  buttons  and presses one of them again within
   three seconds, then the special command corresponding to the button  is
   executed.

   The default special commands are:

   left button
          Reboot the system by signalling the init process

   middle button (if any)
          Execute `/sbin/shutdown -h now'

   right button
          Execute `/sbin/shutdown -r now'

   The  `-S'  command  line  switch enables special command processing and
   allows to change the three special  commands.  To  accept  the  default
   commands  use  `-S  ""'  (i.e., specify an empty argument).  To specify
   your own commands, use  a  colon-separated  list  to  specify  commands
   associated to the left, middle and right button. If any of the commands
   is empty, it is interpreted as `send a signal  to  the  init  process'.
   This  particular  operation  is  supported,  in  addition  to executing
   external commands, because sometimes bad bugs put  the  system  to  the
   impossibility to fork; in these rare case the programmer should be able
   to shutdown the system anyways, and killing init from a running process
   is the only way to do it.

   As an example, `-S ":telinit 1:/sbin/halt"', associates killing init to
   the left button, going single user to the middle one, and  halting  the
   system to the right button.

   System   administrators  should  obviously  be  careful  about  special
   commands, as gpm runs with superuser permissions. Special commands  are
   best  suited  for computers whose mouse can be physically accessed only
   by trusted people.

COMMAND LINE OPTIONS

   Available command line options are the following:

   -a accel
          Set the acceleration value used when a single  motion  event  is
          longer than delta (see `-d').

   -A[limit]
          Start up with selection pasting disabled.  This is intended as a
          security measure; a plausible attack on a system seems to be  to
          stuff  a  nasty shell command into the selection buffer (`rm -rf
          /') including the terminating line break, then  all  the  victim
          has  to  do  is  click the middle mouse button ..  As of version
          1.17.2, this has developed into a more general aging  mechanism;
          the gpm daemon can disable (age) selection pasting automatically
          after a period of inactivity.  To enable this mode just give the
          optional  limit  parameter  (no  space  in  between !)  which is
          interpreted as the time in seconds  for  which  a  selection  is
          considered  valid and pastable.  As of version 1.15.7, a trivial
          program called `disable-paste' is provided. The following  makes
          a good addition to `/etc/profile' if you allow multiple users to
          work on your console.

   `case $( /usr/bin/tty ) in
   /dev/tty[0-9]*) /usr/bin/disable-paste ;;
   esac'

   -b baud
          Set the baud rate.

   -B sequence
          Set the button sequence. `123' is the normal sequence, `321' can
          be used by left-handed people, and `132' can be useful with two-
          button  mice  (especially  within   Emacs).   All   the   button
          permutations are allowable.

   -d delta
          Set  the  delta value. When a single motion event is longer than
          delta, accel is used as a multiplying  factor.  (Must  be  2  or
          above)

   -D     Do  not  automatically  enter background operation when started,
          and log messages to the standard error stream,  not  the  syslog
          mechanism.   This  is useful for debugging; in previous releases
          it was done with a compile-time option.

   -g number
          With glidepoint  devices,  emulate  the  specified  button  with
          tapping.   number  must  be  `1', `2', or `3', and refers to the
          button number before the `-B'  button  remapping  is  performed.
          This  option  applies to the mman and ps2 decoding. No button is
          emulated by default because the ps2 tapping is incompatible with
          some normal ps2 mice

   -h     Print a summary of command line options.

   -i interval
          Set  interval  to  be  used  as an upper time limit for multiple
          clicks. If the interval between button-up and button-down events
          is  less  than limit, the press is considered a double or triple
          click. Time is in milliseconds.

   -k     Kill a running gpm. This can be used by busmouse users  to  kill
          gpm  before  running  X (unless they use `-R' or the single-open
          limitation is removed from the kernel).

   -l charset
          Choose the `inword()' look up table. The charset argument  is  a
          list  of  characters. `-' is used to specify a range and `\ ' is
          used to escape the next character or  to  provide  octal  codes.
          Only  visible  character  can  appear in charset because control
          characters  can't  appear  in  text-mode  video  memory,  whence
          selection is cut.

   -m filename
          Choose the mouse file to open. Must be before -t and -o.

   -M     Enable  multiple  mode. The daemon will read two different mouse
          devices.  Any subsequent option will refer to the second device,
          while  any  preceding  option will be used for the first device.
          This option automatically forces the repeater (`-R') option on.

   -o list-of-extra-options
          The option works similary to the ``-o'' option of mount;  it  is
          used to specify a list of ``extra options'' that are specific to
          each mouse type. The list is comma-separated. The options `dtr',
          `rts'  or `both' are used by the serial initialization to toggle
          the modem lines like, compatibly with earlier gpm versions; note
          however that using -o dtr associated with non-plain-serial mouse
          types may now generate an error.  And by the way, use  -o  after
          -m and after -t.

   -p     Forces  the  pointer  to be visible while selecting. This is the
          behaviour of `selection-1.7', but  it  is  sometimes  confusing.
          The  default  is not to show the pointer, which can be confusing
          as well.

   -r number
          Set the responsiveness as a percentage  of  motion  (1  to  100,
          default  10).  A  lower  number  can be used to slow down cursor
          motion, this can not be used to make a mouse  move  faster,  see
          `-a'.

   -R[name]
          Causes `gpm' to act as a repeater: any mouse data received while
          in graphic mode will be produced on the fifo  `/dev/gpmdata'  in
          protocol  name,  given  as  an  optional  argument  (no space in
          between !).  In principle, you can use the same names as for the
          `-t'  option,  although repeating into some protocols may not be
          implemented for a while.  In addition, you can specify `raw'  as
          the  name,  to  repeat  the mouse data byte by byte, without any
          protocol translation.  If name is omitted, it defaults to `msc'.
          Using  gpm  in  repeater mode, you can configure the X server to
          use its fifo as a mouse device. This option is useful  for  bus-
          mouse  owners to override the single-open limitation. It is also
          an easy way to manage those stupid dual-mode  mice  which  force
          you  to  keep  the middle button down while changing video mode.
          The option is forced on by the `-M' option.

   -s number
          Set the sample rate for the mouse device.

   -S commands
          Enable special-command processing, and optionally specify custom
          commands  as  a  colon-separated  list. See above for a detailed
          description of special commands.

   -t name
          Set the mouse type. Use `-t help' to get  a  list  of  allowable
          types.  Use -t after you selected the mouse device with -m.

   -v     Print version information and exit.

   -2     Force  two  buttons.  This means that the middle button, if any,
          will be taken as it was the right one.

   -3     Force three buttons. By default the mouse is considered to be  a
          2-buttons  one,  until  the  middle  button is pressed. If three
          buttons  are  there,  the  right  one  is  used  to  extend  the
          selection,  and  the middle one is used to paste it.  Beware: if
          you use the `-3' option with a 2-buttons  mouse,  you  won't  be
          able to paste the selection.

OPERATION

   To  select  text  press  the  left mouse button and drag the mouse.  To
   paste text in the same or another console,  press  the  middle  button.
   The right button is used to extend the selection, like in `xterm'.

   Two-button mice use the right button to paste text.

   Double  and triple clicks select whole word and whole lines. Use of the
   `-p' option is recommended for best visual feedback.

   If a trailing space after the contents of a line is highlighted, and if
   there  is  no  other text on the remainder of the line, the rest of the
   line will be selected automatically. If a number of lines are selected,
   highlighted  trailing  spaces  on  each  line  will be removed from the
   selection buffer.

   Any output on the virtual console holding the selection will clear  the
   highlighted  selection  from  the  screen, to maintain integrity of the
   display, although the contents of the paste buffer will be unaffected.

   The selection mechanism is disabled if the controlling virtual  console
   is  placed  in  graphics mode, for example when running X11, and is re-
   enabled when text mode is resumed. (But see BUGS section below.)

BUGS

   The `gpm' server may have problems interacting with X: if your mouse is
   a  single-open  device (i.e. a bus mouse), you should kill `gpm' before
   starting X, or use the `-R' option (see above).   To  kill  `gpm'  just
   invoke `gpm -k'. This problem doesn't apply to serial mice.

   Two instances of gpm can't run on the same system. If you have two mice
   use the `-M' option (see above).

   While the current console is in graphic mode, `gpm' sleeps  until  text
   mode  is  back  (unless `-R' is used). Thus, it won't reply to clients.
   Anyways, it is unlikely that  mouse-eager  clients  will  spur  out  in
   hidden consoles.

   The  clients  shipped  out  with  gpm  are  not updated, thus there are
   potential security risks when using them.

AUTHORS

   Andrew Haylett <ajh@gec-mrc.co.uk> (the original selection code)
   Ian Zimmerman <itz@speakeasy.org> (old maintainer)
   Alessandro Rubini <rubini@linux.it> (old maintainer (still helps a lot))
   Nico Schottelius <nico@schottelius.org> (maintainer)

   Many many contributors, to both selection and gpm.

MAINTAINERS

   The current maintainer is Nico Schottelius. But  without  the  help  of
   Alessandro Rubini and the mailing list it would be impossible for me to
   maintain gpm.  The  development  mailing  list  can  be  reached  under
   gpm@lists.linux.it.  More information on the list is in the README file
   part of the source distribution of gpm.

FILES

   /var/run/gpm.pid The PID of the running gpm
   /dev/gpmctl     A control socket for clients
   /dev/gpmdata    The fifo written to by a repeater (`-R') daemon.

SEE ALSO

    gpm-types(7)  Description of current pointer types supported by gpm

   The info file about `gpm', which gives more  complete  information  and
   explains how to write a gpm client.





Opportunity


Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.

Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.





Free Software


Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.


Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.





Free Books


The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.


Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.





Education


Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.


Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.