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       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.

       -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

               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 stipple 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 the Xorg server, this
               also sets the default for the DontZap  option  to  FALSE.   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.

       -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: TCPIP,  Unix  Domain  sockets,
       DECnet,  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.  or  a  DECnet
       hostname  in  double  colon format (e.g. hydra::) 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 example:


       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.