Xserver - X Window System display server


   X [option ...]


   X  is  the  generic name for the X Window System display server.  It is
   frequently a link or a  copy  of  the  appropriate  server  binary  for
   driving the most frequently used server on a given machine.


   The  X  server  is  usually  started from the X Display Manager program
   xdm(1) or a similar display manager program.  This utility is run  from
   the  system  boot  files  and takes care of keeping the server running,
   prompting for  usernames  and  passwords,  and  starting  up  the  user

   Installations  that run more than one window system may need to use the
   xinit(1) utility instead of a display manager.  However, xinit is to be
   considered  a tool for building startup scripts and is not intended for
   use by end users.  Site administrators are  strongly  urged  to  use  a
   display manager, or build other interfaces for novice users.

   The  X  server  may  also  be started directly by the user, though this
   method is usually reserved for  testing  and  is  not  recommended  for
   normal  operation.   On  some  platforms,  the  user  must have special
   permission to start the X  server,  often  because  access  to  certain
   devices (e.g. /dev/mouse) is restricted.

   When  the  X server starts up, it typically takes over the display.  If
   you are running on a workstation whose console is the display, you  may
   not be able to log into the console while the server is running.


   Many  X  servers  have  device-specific  command line options.  See the
   manual pages for the individual servers for more  details;  a  list  of
   server-specific manual pages is provided in the SEE ALSO section below.

   All  of  the X servers accept the command line options described below.
   Some X servers may have alternative ways of  providing  the  parameters
   described  here,  but  the values provided via the command line options
   should override values specified via other mechanisms.

           The X server runs as the given displaynumber, which by  default
           is  0.   If  multiple  X servers are to run simultaneously on a
           host, each must have a unique display number.  See the  DISPLAY
           NAMES  section  of the X(7) manual page to learn how to specify
           which display number clients should try to use.

   -a number
           sets pointer acceleration  (i.e.  the  ratio  of  how  much  is
           reported to how much the user actually moved the pointer).

   -ac     disables  host-based access control mechanisms.  Enables access
           by any host, and permits any host to modify the access  control
           list.   Use with extreme caution.  This option exists primarily
           for running test suites remotely.

   -audit level
           sets the audit trail level.  The default level  is  1,  meaning
           only  connection rejections are reported.  Level 2 additionally
           reports all successful connections and  disconnects.   Level  4
           enables  messages  from  the  SECURITY  extension,  if present,
           including  generation  and  revocation  of  authorizations  and
           violations of the security policy.  Level 0 turns off the audit
           trail.  Audit lines are sent as standard error output.

   -auth authorization-file
           specifies a file which contains a collection  of  authorization
           records  used  to authenticate access.  See also the xdm(1) and
           Xsecurity(7) manual pages.

   -background none
           Asks the driver not to clear the background on startup, if  the
           driver supports that.  May be useful for smooth transition with
           eg. fbdev driver.  For security reasons this is not the default
           as the screen contents might show a previous user session.

   -br     sets  the  default  root  window  to solid black instead of the
           standard root weave  pattern.    This  is  the  default  unless
           -retro or -wr is specified.

   -bs     disables backing store support on all screens.

   -c      turns off key-click.

   c volume
           sets key-click volume (allowable range: 0-100).

   -cc class
           sets  the  visual  class  for the root window of color screens.
           The class numbers are as specified  in  the  X  protocol.   Not
           obeyed by all servers.

   -core   causes the server to generate a core dump on fatal errors.

   -displayfd fd
           specifies  a  file descriptor in the launching process.  Rather
           than specify a display number, the X  server  will  attempt  to
           listen on successively higher display numbers, and upon finding
           a free one, will write the display number  back  on  this  file
           descriptor  as  a newline-terminated string.  The -pn option is
           ignored when using -displayfd.

   -deferglyphs whichfonts
           specifies the types  of  fonts  for  which  the  server  should
           attempt  to  use deferred glyph loading.  whichfonts can be all
           (all fonts), none (no fonts), or 16 (16 bit fonts only).

   -dpi resolution
           sets the resolution for all screens, in dots per inch.   To  be
           used  when  the server cannot determine the screen size(s) from
           the hardware.

   dpms    enables  DPMS  (display  power  management   services),   where
           supported.   The  default  state  is platform and configuration

   -dpms   disables DPMS (display power management services).  The default
           state is platform and configuration specific.

           disables  named  extension.    If  an unknown extension name is
           specified, a list of accepted extension names is printed.

           enables named extension.   If  an  unknown  extension  name  is
           specified, a list of accepted extension names is printed.

   -f volume
           sets beep (bell) volume (allowable range: 0-100).

   -fc cursorFont
           sets default cursor font.

   -fn font
           sets the default font.

   -fp fontPath
           sets the search path for fonts.  This path is a comma separated
           list of directories  which  the  X  server  searches  for  font
           databases.   See the FONTS section of this manual page for more
           information and the default list.

   -help   prints a usage message.

   -I      causes all remaining command line arguments to be ignored.

   -iglx   Prohibit creating indirect GLX contexts.  Indirect  GLX  is  of
           limited  use,  since  it  lacks  support for many modern OpenGL
           features and extensions; it's slower than direct contexts;  and
           it  opens  a  large attack surface for protocol parsing errors.
           This is the default unless +iglx is specified.

   +iglx   Allow creating indirect GLX contexts.

   -maxbigreqsize size
           sets the maximum big request to size MB.

           disable the display of the pointer cursor.

   -nolisten trans-type
           disables a transport type.  For example, TCP/IP connections can
           be  disabled  with  -nolisten  tcp.   This option may be issued
           multiple times to  disable  listening  to  different  transport
           types.   Supported  transport types are platform dependent, but
           commonly include:

           tcp     TCP over IPv4 or IPv6
           inet    TCP over IPv4 only
           inet6   TCP over IPv6 only
           unix    UNIX Domain Sockets
           local   Platform preferred local connection method

   -listen trans-type
           enables a transport type.  For example, TCP/IP connections  can
           be  enabled  with  -listen  tcp.   This  option  may  be issued
           multiple times  to  enable  listening  to  different  transport

           prevents  a  server  reset  when  the last client connection is
           closed.  This overrides  a  previous  -terminate  command  line

   -p minutes
           sets screen-saver pattern cycle time in minutes.

   -pn     permits the server to continue running if it fails to establish
           all of its well-known sockets (connection points for  clients),
           but establishes at least one.  This option is set by default.

   -nopn   causes  the  server to exit if it fails to establish all of its
           well-known sockets (connection points for clients).

   -r      turns off auto-repeat.

   r       turns on auto-repeat.

   -retro  starts the server with the classic stipple and cursor  visible.
           The  default  is  to  start  with  a  black root window, and to
           suppress  display  of  the  cursor  until  the  first  time  an
           application  calls  XDefineCursor().  For  kdrive servers, this
           implies -zap.

   -s minutes
           sets screen-saver timeout time in minutes.

   -su     disables save under support on all screens.

   -seat seat
           seat to run on. Takes a string identifying a seat in a platform
           specific  syntax.  On platforms which support this feature this
           may be used to limit the  server  to  expose  only  a  specific
           subset of devices connected to the system.

   -t number
           sets  pointer  acceleration threshold in pixels (i.e. after how
           many pixels pointer acceleration should take effect).

           causes the server to terminate  at  server  reset,  instead  of
           continuing  to run.  This overrides a previous -noreset command
           line option.

   -to seconds
           sets default connection timeout in seconds.

   -tst    disables  all   testing   extensions   (e.g.,   XTEST,   XTrap,
           XTestExtension1, RECORD).

   ttyxx   ignored, for servers started the ancient way (from init).

   v       sets video-off screen-saver preference.

   -v      sets video-on screen-saver preference.

   -wm     forces   the   default  backing-store  of  all  windows  to  be
           WhenMapped.  This is a backdoor way of getting backing-store to
           apply  to  all  windows.  Although all mapped windows will have
           backing store, the backing store attribute  value  reported  by
           the server for a window will be the last value established by a
           client.  If it has never been set by a client, the server  will
           report the default value, NotUseful.  This behavior is required
           by the X protocol,  which  allows  the  server  to  exceed  the
           client's  backing store expectations but does not provide a way
           to tell the client that it is doing so.

   -wr     sets the default root window to  solid  white  instead  of  the
           standard root weave pattern.

   -x extension
           loads  the  specified  extension  at init.  This is a no-op for
           most implementations.

           enables(+) or disables(-) the XINERAMA extension.  The  default
           state is platform and configuration specific.


   Some X servers accept the following options:

   -ld kilobytes
           sets the data space limit of the server to the specified number
           of kilobytes.  A value of zero makes the data size as large  as
           possible.   The default value of -1 leaves the data space limit

   -lf files
           sets the  number-of-open-files  limit  of  the  server  to  the
           specified  number.  A value of zero makes the limit as large as
           possible.  The default value of -1 leaves the limit unchanged.

   -ls kilobytes
           sets the stack space limit  of  the  server  to  the  specified
           number  of  kilobytes.  A value of zero makes the stack size as
           large as possible.  The default value of -1  leaves  the  stack
           space limit unchanged.

           64|128|256|512  Set  the  maximum  number of clients allowed to
           connect to the X server.  Acceptable values are 64, 128, 256 or

   -render default|mono|gray|color  sets  the color allocation policy that
           will be used by the render extension.

           default selects the default  policy  defined  for  the  display
                   depth of the X server.

           mono    don't use any color cell.

           gray    use  a  gray  map  of  13  color cells for the X render

           color   use a color cube of at most 4*4*4 colors  (that  is  64
                   color cells).

           disables  smart  scheduling on platforms that support the smart

   -schedInterval interval
           sets the smart  scheduler's  scheduling  interval  to  interval


   X  servers  that  support  XDMCP have the following options.  See the X
   Display Manager Control Protocol specification for more information.

   -query hostname
           enables  XDMCP  and  sends  Query  packets  to  the   specified

           enable  XDMCP  and  broadcasts  BroadcastQuery  packets  to the
           network.  The first responding display manager will  be  chosen
           for the session.

   -multicast [address [hop count]]
           Enable  XDMCP  and  multicast  BroadcastQuery  packets  to  the
           network.  The first responding display manager  is  chosen  for
           the session.  If an address is specified, the multicast is sent
           to that address.  If no address is specified, the multicast  is
           sent to the default XDMCP IPv6 multicast group.  If a hop count
           is specified, it is used as  the  maximum  hop  count  for  the
           multicast.   If no hop count is specified, the multicast is set
           to a maximum of 1 hop, to  prevent  the  multicast  from  being
           routed beyond the local network.

   -indirect hostname
           enables  XDMCP  and send IndirectQuery packets to the specified

   -port port-number
           uses the specified port-number for XDMCP  packets,  instead  of
           the  default.  This option must be specified before any -query,
           -broadcast, -multicast, or -indirect options.

   -from local-address
           specifies the local address to  connect  from  (useful  if  the
           connecting  host  has multiple network interfaces).  The local-
           address may be expressed in any form  acceptable  to  the  host
           platform's gethostbyname(3) implementation.

   -once   causes  the  server  to  terminate (rather than reset) when the
           XDMCP session ends.

   -class display-class
           XDMCP has an additional  display  qualifier  used  in  resource
           lookup  for  display-specific  options.   This option sets that
           value, by default it is "MIT-unspecified" (not  a  very  useful

   -cookie xdm-auth-bits
           When  testing  XDM-AUTHENTICATION-1,  a  private  key is shared
           between the server and the manager.  This option sets the value
           of that private data (not that it is very private, being on the
           command line!).

   -displayID display-id
           Yet another XDMCP specific value, this one allows  the  display
           manager  to  identify  each  display  so that it can locate the
           shared key.


   X servers that support the XKEYBOARD (a.k.a.  "XKB")  extension  accept
   the  following options.  All layout files specified on the command line
   must be located in the  XKB  base  directory  or  a  subdirectory,  and
   specified  as  the  relative  path  from  the  XKB base directory.  The
   default XKB base directory is /usr/lib/X11/xkb.

   [+-]accessx [ timeout [ timeout_mask [ feedback [ options_mask ] ] ] ]
           enables(+) or disables(-) AccessX key sequences.

   -xkbdir directory
           base directory for keyboard layout files.  This option  is  not
           available  for setuid X servers (i.e., when the X server's real
           and effective uids are different).

   -ardelay milliseconds
           sets the autorepeat delay (length of time in milliseconds  that
           a key must be depressed before autorepeat starts).

   -arinterval milliseconds
           sets  the  autorepeat  interval (length of time in milliseconds
           that should elapse between autorepeat-generated keystrokes).

   -xkbmap filename
           loads keyboard description in filename on server startup.


   The X server  supports  client  connections  via  a  platform-dependent
   subset  of  the following transport types: TCP/IP, Unix Domain sockets,
   and several varieties of SVR4 local connections.  See the DISPLAY NAMES
   section of the X(7) manual page to learn how to specify which transport
   type clients should try to use.


   The X server implements a platform-dependent subset  of  the  following
   authorization  protocols: MIT-MAGIC-COOKIE-1, XDM-AUTHORIZATION-1, XDM-
   AUTHORIZATION-2, SUN-DES-1, and MIT-KERBEROS-5.  See  the  Xsecurity(7)
   manual page for information on the operation of these protocols.

   Authorization  data  required  by  the above protocols is passed to the
   server in a private file named with  the  -auth  command  line  option.
   Each  time  the  server is about to accept the first connection after a
   reset (or when the server is starting), it reads this  file.   If  this
   file  contains  any  authorization  records,  the  local  host  is  not
   automatically allowed access to the server, and only clients which send
   one  of  the  authorization  records  contained  in  the  file  in  the
   connection setup information will  be  allowed  access.   See  the  Xau
   manual  page  for a description of the binary format of this file.  See
   xauth(1) for maintenance of this file, and distribution of its contents
   to remote hosts.

   The  X  server  also uses a host-based access control list for deciding
   whether or not to accept  connections  from  clients  on  a  particular
   machine.   If no other authorization mechanism is being used, this list
   initially consists of the host on which the server is running  as  well
   as  any  machines  listed  in  the  file  /etc/Xn.hosts, where n is the
   display number of the server.  Each line of  the  file  should  contain
   either  an Internet hostname (e.g. expo.lcs.mit.edu) or a complete name
   in the format family:name as described in  the  xhost(1)  manual  page.
   There  should  be  no  leading  or  trailing  spaces on any lines.  For


   Users can add or remove hosts from this  list  and  enable  or  disable
   access  control  using  the  xhost command from the same machine as the

   If the X FireWall Proxy (xfwp) is  being  used  without  a  sitepolicy,
   host-based  authorization  must  be turned on for clients to be able to
   connect to the X server via  the  xfwp.   If  xfwp  is  run  without  a
   configuration  file and thus no sitepolicy is defined, if xfwp is using
   an X server  where  xhost  +  has  been  run  to  turn  off  host-based
   authorization  checks,  when a client tries to connect to this X server
   via xfwp, the X server will deny the connection.  See xfwp(1) for  more
   information about this proxy.

   The  X  protocol  intrinsically  does  not  have  any  notion of window
   operation permissions or place any restrictions on what  a  client  can
   do;  if  a  program  can  connect  to a display, it has full run of the
   screen.  X servers that support  the  SECURITY  extension  fare  better
   because  clients can be designated untrusted via the authorization they
   use to connect; see the xauth(1) manual page for details.  Restrictions
   are imposed on untrusted clients that curtail the mischief they can do.
   See the SECURITY extension specification for a complete list  of  these

   Sites  that  have better authentication and authorization systems might
   wish to make use of the hooks  in  the  libraries  and  the  server  to
   provide additional security models.


   The X server attaches special meaning to the following signals:

   SIGHUP  This   signal   causes   the   server  to  close  all  existing
           connections, free all resources, and restore all defaults.   It
           is  sent  by  the display manager whenever the main user's main
           application (usually an xterm or window manager) exits to force
           the server to clean up and prepare for the next user.

   SIGTERM This signal causes the server to exit cleanly.

   SIGUSR1 This signal is used quite differently from either of the above.
           When the server starts, it checks to see if  it  has  inherited
           SIGUSR1 as SIG_IGN instead of the usual SIG_DFL.  In this case,
           the server sends a SIGUSR1 to its parent process after  it  has
           set  up  the various connection schemes.  Xdm uses this feature
           to recognize when connecting to the server is possible.


   The X server  can  obtain  fonts  from  directories  and/or  from  font
   servers.   The  list  of directories and font servers the X server uses
   when trying to open a font is controlled by the font path.

   The            default             font             path             is
   ins .

   A special kind of directory  can  be  specified  using  the  catalogue:
   prefix. Directories specified this way can contain symlinks pointing to
   the real font directories. See the FONTPATH.D section for details.

   The font path can be set with the -fp option or by  xset(1)  after  the
   server has started.


   You   can   specify   a   special   kind  of  font  path  in  the  form
   catalogue:<dir>.  The directory specified after the  catalogue:  prefix
   will be scanned for symlinks and each symlink destination will be added
   as a local fontfile FPE.

   The symlink can be suffixed by attributes  such  as  'unscaled',  which
   will  be  passed  through  to  the  underlying  fontfile  FPE. The only
   exception is the newly introduced 'pri' attribute, which will  be  used
   for ordering the font paths specified by the symlinks.

   An example configuration:

       75dpi:unscaled:pri=20 -> /usr/share/X11/fonts/75dpi
       ghostscript:pri=60 -> /usr/share/fonts/default/ghostscript
       misc:unscaled:pri=10 -> /usr/share/X11/fonts/misc
       type1:pri=40 -> /usr/share/X11/fonts/Type1
       type1:pri=50 -> /usr/share/fonts/default/Type1

   This  will  add  /usr/share/X11/fonts/misc  as  the  first FPE with the
   attribute 'unscaled', second FPE  will  be  /usr/share/X11/fonts/75dpi,
   also with the attribute 'unscaled' etc. This is functionally equivalent
   to setting the following font path:



   /etc/Xn.hosts                 Initial access control list  for  display
                                 number n

                                 Bitmap font directories

                                 Outline font directories

   /tmp/.X11-unix/Xn             Unix domain socket for display number n

   /usr/adm/Xnmsgs               Error log file for display  number  n  if
                                 run from init(8)

   /usr/lib/X11/xdm/xdm-errors   Default  error  log file if the server is
                                 run from xdm(1)


   General information: X(7)

   Protocols: X Window System Protocol, The X  Font  Service  Protocol,  X
   Display Manager Control Protocol

   Fonts:  bdftopcf(1), mkfontdir(1), mkfontscale(1), xfs(1), xlsfonts(1),
   xfontsel(1), xfd(1), X Logical Font Description Conventions

   Keyboards: xkeyboard-config(7)

   Security: Xsecurity(7), xauth(1), Xau(1),  xdm(1),  xhost(1),  xfwp(1),
   Security Extension Specification

   Starting the server: startx(1), xdm(1), xinit(1)

   Controlling  the  server  once started: xset(1), xsetroot(1), xhost(1),
   xinput(1), xrandr(1)

   Server-specific  man  pages:  Xorg(1),  Xdmx(1),  Xephyr(1),  Xnest(1),
   Xvfb(1), Xquartz(1), XWin(1).

   Server  internal documentation: Definition of the Porting Layer for the
   X v11 Sample Server


   The sample server was originally written by Susan Angebranndt,  Raymond
   Drewry,  Philip  Karlton,  and  Todd  Newman,  from  Digital  Equipment
   Corporation, with support  from  a  large  cast.   It  has  since  been
   extensively  rewritten  by  Keith  Packard and Bob Scheifler, from MIT.
   Dave Wiggins took over post-R5 and made substantial improvements.


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