Man Linux: Main Page and Category List


       X - a portable, network-transparent window system


       The  X  Window System is a network transparent window system which runs
       on a wide range of computing  and  graphics  machines.   It  should  be
       relatively  straightforward  to  build  the  X.Org  Foundation software
       distribution on most ANSI C and POSIX  compliant  systems.   Commercial
       implementations are also available for a wide range of platforms.

       The  X.Org  Foundation  requests  that the following names be used when
       referring to this software:

                                   X Window System
                                    X Version 11
                             X Window System, Version 11

       X Window System is a trademark of The Open Group.


       X Window System servers run on computers  with  bitmap  displays.   The
       server  distributes  user  input  to  and  accepts output requests from
       various client programs through a  variety  of  different  interprocess
       communication  channels.   Although  the  most  common  case is for the
       client programs to be running  on  the  same  machine  as  the  server,
       clients  can  be  run  transparently  from  other  machines  (including
       machines with different architectures and operating systems) as well.

       X supports overlapping hierarchical subwindows and  text  and  graphics
       operations,  on  both  monochrome  and  color  displays.   For  a  full
       explanation of the functions that are  available,  see  the  Xlib  -  C
       Language   X   Interface   manual,   the   X   Window  System  Protocol
       specification, the X Toolkit Intrinsics - C Language Interface  manual,
       and various toolkit documents.

       The number of programs that use X is quite large.  Programs provided in
       the core X.Org Foundation distribution include:  a  terminal  emulator,
       xterm;  a  window  manager,  twm;  a  display  manager,  xdm; a console
       redirect program, xconsole; a mail interface,  xmh;  a  bitmap  editor,
       bitmap;  resource  listing/manipulation  tools, appres, editres; access
       control programs, xauth, xhost, and iceauth;  user  preference  setting
       programs,  xrdb, xcmsdb, xset, xsetroot, xstdcmap, and xmodmap; clocks,
       xclock and  oclock;  a  font  displayer,  xfd;  utilities  for  listing
       information  about  fonts,  windows,  and displays, xlsfonts, xwininfo,
       xlsclients, xdpyinfo, xlsatoms, and xprop;  screen  image  manipulation
       utilities,  xwd,  xwud,  and  xmag;  a performance measurement utility,
       x11perf;  a  font  compiler,  bdftopcf;  a  font  server  and   related
       utilities,  xfs,  fsinfo,  fslsfonts,  fstobdf;  a  display  server and
       related  utilities,  Xserver,  rgb,  mkfontdir;  a  clipboard  manager,
       xclipboard;   keyboard  description  compiler  and  related  utilities,
       xkbcomp, setxkbmap xkbprint, xkbbell, xkbevd, xkbvleds, and xkbwatch; a
       utility to terminate clients, xkill; a firewall security proxy, xfwp; a
       proxy manager to control them, proxymngr; a utility  to  find  proxies,
       xfindproxy;  web  browser  plug-ins, and; an RX
       MIME-type helper program, xrx; and a utility to cause part  or  all  of
       the screen to be redrawn, xrefresh.

       Many  other  utilities,  window  managers,  games,  toolkits,  etc. are
       included  as  user-contributed  software  in   the   X.Org   Foundation
       distribution,  or  are  available  on  the  Internet.   See  your  site
       administrator for details.


       There are two main ways of getting the X server and an initial  set  of
       client  applications  started.   The  particular method used depends on
       what operating system you are running and whether or not you use  other
       window systems in addition to X.

       Display Manager
               If you want to always have X running on your display, your site
               administrator can set your machine up to use a Display  Manager
               such as xdm, gdm, or kdm.  This program is typically started by
               the system at boot time and takes care of  keeping  the  server
               running and getting users logged in.  If you are running one of
               these display managers, you will normally see a window  on  the
               screen  welcoming  you  to the system and asking for your login
               information.  Simply type them in as  you  would  at  a  normal
               terminal.   If  you  make  a  mistake, the display manager will
               display an error message and ask you to try again.   After  you
               have  successfully logged in, the display manager will start up
               your X environment.  The documentation for the display  manager
               you use can provide more details.

       xinit (run manually from the shell)
               Sites  that support more than one window system might choose to
               use the xinit program for starting X manually.  If this is true
               for  your  machine,  your site administrator will probably have
               provided a program named "x11", "startx", or "xstart" that will
               do  site-specific  initialization  (such  as loading convenient
               default resources,  running  a  window  manager,  displaying  a
               clock,  and starting several terminal emulators) in a nice way.
               If not, you can build such a script using  the  xinit  program.
               This  utility  simply  runs one user-specified program to start
               the server, runs another to start up any desired  clients,  and
               then  waits  for either to finish.  Since either or both of the
               user-specified programs may  be  a  shell  script,  this  gives
               substantial  flexibility  at  the  expense of a nice interface.
               For this reason, xinit is not intended for end users.


       From the user’s perspective, every X server has a display name  of  the


       This  information is used by the application to determine how it should
       connect to the server and which screen it should  use  by  default  (on
       displays with multiple monitors):

               The  hostname  specifies  the  name of the machine to which the
               display is physically connected.  If the hostname is not given,
               the most efficient way of communicating to a server on the same
               machine will be used.

               The phrase "display" is usually used to refer to collection  of
               monitors  that  share  a common set of input devices (keyboard,
               mouse, tablet, etc.).  Most workstations tend to only have  one
               display.   Larger, multi-user systems, however, frequently have
               several displays so that more than  one  person  can  be  doing
               graphics  work  at once.  To avoid confusion, each display on a
               machine is assigned a display number (beginning at 0) when  the
               X  server for that display is started.  The display number must
               always be given in a display name.

               Some displays share their  input  devices  among  two  or  more
               monitors.   These may be configured as a single logical screen,
               which allows windows to move across screens, or  as  individual
               screens,  each  with  their  own set of windows.  If configured
               such that each monitor has its own set of windows, each  screen
               is  assigned a screen number (beginning at 0) when the X server
               for that display is started.   If  the  screen  number  is  not
               given, screen 0 will be used.

       On  POSIX  systems,  the default display name is stored in your DISPLAY
       environment variable.  This variable is set automatically by the  xterm
       terminal  emulator.   However,  when  you log into another machine on a
       network, you may need to set DISPLAY by hand to point to your  display.
       For example,

           % setenv DISPLAY myws:0
           $ DISPLAY=myws:0; export DISPLAY
       The  ssh program can be used to start an X program on a remote machine;
       it automatically sets the DISPLAY variable correctly.

       Finally, most X programs accept  a  command  line  option  of  -display
       displayname  to  temporarily override the contents of DISPLAY.  This is
       most commonly used to pop windows on another person’s screen or as part
       of  a  "remote  shell"  command to start an xterm pointing back to your
       display.  For example,

           % xeyes -display joesws:0 -geometry 1000x1000+0+0
           % rsh big xterm -display myws:0 -ls </dev/null &

       X  servers  listen  for  connections  on   a   variety   of   different
       communications  channels  (network  byte streams, shared memory, etc.).
       Since there can be more than one way of contacting a given server,  The
       hostname  part  of  the  display  name is used to determine the type of
       channel (also  called  a  transport  layer)  to  be  used.   X  servers
       generally support the following types of connections:

               The  hostname  part  of  the  display  name should be the empty
               string.  For example:  :0, :1, and :0.1.   The  most  efficient
               local transport will be chosen.

               The  hostname  part  of  the  display name should be the server
               machine’s  hostname  or  IP  address.   Full  Internet   names,
               abbreviated  names,  IPv4 addresses, and IPv6 addresses are all
               allowed.     For    example:,    expo:0,    [::1]:0,
     , bigmachine:1, and hydra:0.1.

               The  hostname  part  of  the  display name should be the server
               machine’s nodename, followed by two colons instead of one.  For
               example:  myws::0, big::1, and hydra::0.1.


       An  X  server  can  use  several  types  of access control.  Mechanisms
       provided in Release 7 are:
           Host Access                   Simple host-based access control.
           MIT-MAGIC-COOKIE-1            Shared plain-text "cookies".
           XDM-AUTHORIZATION-1           Secure DES based private-keys.
           SUN-DES-1                     Based on Sun’s secure rpc system.
           Server Interpreted            Server-dependent methods of access control

       Xdm  initializes  access  control  for  the  server  and  also   places
       authorization  information in a file accessible to the user.  Normally,
       the list of hosts from which connections are always accepted should  be
       empty,  so that only clients with are explicitly authorized can connect
       to the display.  When you add entries to the host  list  (with  xhost),
       the  server  no  longer  performs any authorization on connections from
       those machines.  Be careful with this.

       The file from which Xlib extracts authorization data can  be  specified
       with  the  environment  variable  XAUTHORITY,  and defaults to the file
       .Xauthority in the home directory.  Xdm uses $HOME/.Xauthority and will
       create it or merge in authorization records if it already exists when a
       user logs in.

       If you use several machines and share a common  home  directory  across
       all of the machines by means of a network file system, you never really
       have to  worry  about  authorization  files,  the  system  should  work
       correctly  by  default.   Otherwise,  as  the  authorization  files are
       machine-independent, you can simply copy the files to share  them.   To
       manage  authorization  files,  use  xauth.   This program allows you to
       extract records and insert them into other files.  Using this, you  can
       send  authorization  to  remote  machines when you login, if the remote
       machine does not share a common home directory with your local machine.
       Note  that  authorization  information  transmitted  ‘‘in  the  clear’’
       through a network file system or using ftp or rcp can be ‘‘stolen’’  by
       a network eavesdropper, and as such may enable unauthorized access.  In
       many environments, this level of security is not a concern, but  if  it
       is,   you   need   to  know  the  exact  semantics  of  the  particular
       authorization data to know if this is actually a problem.

       For more information on access control, see the Xsecurity manual  page.


       One  of  the  advantages  of  using window systems instead of hardwired
       terminals is that  applications  don’t  have  to  be  restricted  to  a
       particular  size  or  location  on  the screen.  Although the layout of
       windows on a display is controlled by the window manager that the  user
       is  running  (described  below),  most X programs accept a command line
       argument of the form  -geometry  WIDTHxHEIGHT+XOFF+YOFF  (where  WIDTH,
       HEIGHT, XOFF, and YOFF are numbers) for specifying a preferred size and
       location for this application’s main window.

       The WIDTH and HEIGHT parts of the geometry  specification  are  usually
       measured  in either pixels or characters, depending on the application.
       The XOFF and YOFF parts are measured in pixels and are used to  specify
       the  distance  of  the window from the left or right and top and bottom
       edges of the screen, respectively.  Both types of offsets are  measured
       from  the indicated edge of the screen to the corresponding edge of the
       window.  The X offset may be specified in the following ways:

       +XOFF   The left edge of the window is to be placed XOFF pixels in from
               the  left  edge  of  the  screen (i.e., the X coordinate of the
               window’s origin will be XOFF).  XOFF may be negative, in  which
               case the window’s left edge will be off the screen.

       -XOFF   The  right  edge  of  the window is to be placed XOFF pixels in
               from the right edge of the screen.  XOFF may  be  negative,  in
               which case the window’s right edge will be off the screen.

       The Y offset has similar meanings:

       +YOFF   The  top  edge of the window is to be YOFF pixels below the top
               edge of the screen (i.e., the  Y  coordinate  of  the  window’s
               origin  will be YOFF).  YOFF may be negative, in which case the
               window’s top edge will be off the screen.

       -YOFF   The bottom edge of the window is to be YOFF  pixels  above  the
               bottom edge of the screen.  YOFF may be negative, in which case
               the window’s bottom edge will be off the screen.

       Offsets must be given as pairs; in other words,  in  order  to  specify
       either XOFF or YOFF both must be present.  Windows can be placed in the
       four corners of the screen using the following specifications:

       +0+0    upper left hand corner.

       -0+0    upper right hand corner.

       -0-0    lower right hand corner.

       +0-0    lower left hand corner.

       In the following examples, a terminal emulator is placed in roughly the
       center of the screen and a load average monitor, mailbox, and clock are
       placed in the upper right hand corner:

           xterm -fn 6x10 -geometry 80x24+30+200 &
           xclock -geometry 48x48-0+0 &
           xload -geometry 48x48-96+0 &
           xbiff -geometry 48x48-48+0 &


       The layout of windows on the screen is controlled by  special  programs
       called  window  managers.   Although  many  window  managers will honor
       geometry specifications as given, others  may  choose  to  ignore  them
       (requiring  the  user  to  explicitly  draw  the window’s region on the
       screen with the pointer, for example).

       Since window managers are regular (albeit complex) client  programs,  a
       variety   of  different  user  interfaces  can  be  built.   The  X.Org
       Foundation distribution comes with a window  manager  named  twm  which
       supports overlapping windows, popup menus, point-and-click or click-to-
       type input models, title bars, nice icons  (and  an  icon  manager  for
       those who don’t like separate icon windows).

       See  the user-contributed software in the X.Org Foundation distribution
       for other popular window managers.


       Collections of characters for displaying text  and  symbols  in  X  are
       known  as  fonts.  A font typically contains images that share a common
       appearance  and  look  nice  together  (for  example,  a  single  size,
       boldness,  slant,  and character set).  Similarly, collections of fonts
       that are based on a common type face (the variations are usually called
       roman, bold, italic, bold italic, oblique, and bold oblique) are called

       Fonts come in various sizes.  The X  server  supports  scalable  fonts,
       meaning it is possible to create a font of arbitrary size from a single
       source for the font.  The server supports scaling  from  outline  fonts
       and   bitmap  fonts.   Scaling  from  outline  fonts  usually  produces
       significantly better results than scaling from bitmap fonts.

       An  X  server  can  obtain  fonts  from  individual  files  stored   in
       directories  in  the  file system, or from one or more font servers, or
       from a mixtures of directories and font servers.  The  list  of  places
       the  server  looks when trying to find a font is controlled by its font
       path.  Although most installations will choose to have the server start
       up with all of the commonly used font directories in the font path, the
       font path can be changed at any time with the xset  program.   However,
       it  is  important  to  remember  that  the  directory  names are on the
       server’s machine, not on the application’s.

       Bitmap font files are usually  created  by  compiling  a  textual  font
       description  into  binary  form,  using  bdftopcf.   Font databases are
       created by running the mkfontdir program in  the  directory  containing
       the source or compiled versions of the fonts.  Whenever fonts are added
       to a directory, mkfontdir should be rerun so that the server  can  find
       the  new fonts.  To make the server reread the font database, reset the
       font path with the xset program.  For example,  to  add  a  font  to  a
       private directory, the following commands could be used:

           % cp newfont.pcf ~/myfonts
           % mkfontdir ~/myfonts
           % xset fp rehash

       The  xfontsel  and  xlsfonts programs can be used to browse through the
       fonts available on a server.  Font names tend to be fairly long as they
       contain  all  of the information needed to uniquely identify individual
       fonts.  However, the X server supports wildcarding of  font  names,  so
       the full specification


       might be abbreviated as:


       Because  the  shell  also  has special meanings for * and ?, wildcarded
       font names should be quoted:

           % xlsfonts -fn ’-*-courier-medium-r-normal--*-100-*-*-*-*-*-*’

       The xlsfonts program can be used to list all of the fonts that match  a
       given  pattern.  With no arguments, it lists all available fonts.  This
       will usually list the same font at many different sizes.  To  see  just
       the base scalable font names, try using one of the following patterns:


       To  convert  one of the resulting names into a font at a specific size,
       replace one of the first two zeros with a  nonzero  value.   The  field
       containing  the  first  zero  is  for the pixel size; replace it with a
       specific height in pixels to name a font at that size.   Alternatively,
       the  field containing the second zero is for the point size; replace it
       with a specific size in decipoints (there are 722.7 decipoints  to  the
       inch)  to  name a font at that size.  The last zero is an average width
       field, measured in tenths of pixels; some servers  will  anamorphically
       scale if this value is specified.


       One  of  the  following  forms  can  be used to name a font server that
       accepts TCP connections:


       The hostname specifies the name (or decimal  numeric  address)  of  the
       machine  on  which the font server is running.  The port is the decimal
       TCP port on which the font server is listening  for  connections.   The
       cataloguelist  specifies  a  list  of  catalogue  names,  with ’+’ as a

       Examples: tcp/, tcp/

       One of the following forms can be used  to  name  a  font  server  that
       accepts DECnet connections:


       The  nodename  specifies  the  name (or decimal numeric address) of the
       machine on which the font server is running.  The objname is a  normal,
       case-insensitive  DECnet  object  name.   The cataloguelist specifies a
       list of catalogue names, with ’+’ as a separator.

       Examples:                                  DECnet/SRVNOD::FONT$DEFAULT,


       Most  applications provide ways of tailoring (usually through resources
       or command line arguments) the colors of various elements in  the  text
       and  graphics  they  display.   A  color  can be specified either by an
       abstract color name,  or  by  a  numerical  color  specification.   The
       numerical specification can identify a color in either device-dependent
       (RGB) or device-independent terms.  Color strings are case-insensitive.

       X supports the use of abstract color names, for example, "red", "blue".
       A value for this abstract name is obtained by  searching  one  or  more
       color  name  databases.   Xlib  first searches zero or more client-side
       databases; the number, location, and  content  of  these  databases  is
       implementation  dependent.   If  the  name  is  not found, the color is
       looked up in the X server’s database.  The text form of  this  database
       is commonly stored in the file usr/share/X11/rgb.txt.

       A  numerical  color  specification consists of a color space name and a
       set of values in the following syntax:


       An RGB Device specification is identified by the prefix "rgb:" and  has
       the following syntax:


               <red>, <green>, <blue> := h | hh | hhh | hhhh
               h := single hexadecimal digits
       Note  that  h indicates the value scaled in 4 bits, hh the value scaled
       in 8 bits, hhh the value scaled in 12 bits, and hhhh the  value  scaled
       in  16  bits,  respectively.  These values are passed directly to the X
       server, and are assumed to be gamma corrected.

       The eight primary colors can be represented as:

           black                rgb:0/0/0
           red                  rgb:ffff/0/0
           green                rgb:0/ffff/0
           blue                 rgb:0/0/ffff
           yellow               rgb:ffff/ffff/0
           magenta              rgb:ffff/0/ffff
           cyan                 rgb:0/ffff/ffff
           white                rgb:ffff/ffff/ffff

       For  backward  compatibility,  an  older  syntax  for  RGB  Device   is
       supported,  but  its continued use is not encouraged.  The syntax is an
       initial sharp sign character followed by a  numeric  specification,  in
       one of the following formats:

           #RGB                      (4 bits each)
           #RRGGBB                   (8 bits each)
           #RRRGGGBBB                (12 bits each)
           #RRRRGGGGBBBB             (16 bits each)

       The  R,  G, and B represent single hexadecimal digits.  When fewer than
       16 bits each are specified, they represent the most-significant bits of
       the  value (unlike the "rgb:" syntax, in which values are scaled).  For
       example, #3a7 is the same as #3000a0007000.

       An RGB intensity specification is identified by the prefix "rgbi:"  and
       has the following syntax:


       The red, green, and blue are floating point values between 0.0 and 1.0,
       inclusive.  They represent linear intensity values, with 1.0 indicating
       full  intensity,  0.5  half intensity, and so on.  These values will be
       gamma corrected by Xlib before being sent to the X server.   The  input
       format  for  these  values  is  an  optional  sign, a string of numbers
       possibly containing a decimal point, and  an  optional  exponent  field
       containing an E or e followed by a possibly signed integer string.

       The   standard   device-independent   string  specifications  have  the
       following syntax:

           CIEXYZ:<X>/<Y>/<Z>             (none, 1, none)
           CIEuvY:<u>/<v>/<Y>             (~.6, ~.6, 1)
           CIExyY:<x>/<y>/<Y>             (~.75, ~.85, 1)
           CIELab:<L>/<a>/<b>             (100, none, none)
           CIELuv:<L>/<u>/<v>             (100, none, none)
           TekHVC:<H>/<V>/<C>             (360, 100, 100)

       All of the values (C, H, V, X, Y, Z, a, b, u, v,  y,  x)  are  floating
       point  values.   Some  of the values are constrained to be between zero
       and some upper bound; the upper bounds are given in parentheses  above.
       The syntax for these values is an optional ’+’ or ’-’ sign, a string of
       digits possibly containing a decimal point, and  an  optional  exponent
       field  consisting  of  an ’E’ or ’e’ followed by an optional ’+’ or ’-’
       followed by a string of digits.

       For  more  information  on  device  independent  color,  see  the  Xlib
       reference manual.


       The  X keyboard model is broken into two layers:  server-specific codes
       (called keycodes)  which  represent  the  physical  keys,  and  server-
       independent  symbols  (called  keysyms)  which represent the letters or
       words that appear on the keys.  Two tables are kept in the  server  for
       converting keycodes to keysyms:

       modifier list
               Some  keys (such as Shift, Control, and Caps Lock) are known as
               modifier and are used to  select  different  symbols  that  are
               attached  to  a single key (such as Shift-a generates a capital
               A, and Control-l generates a control character ^L).  The server
               keeps  a list of keycodes corresponding to the various modifier
               keys.  Whenever a  key  is  pressed  or  released,  the  server
               generates  an  event that contains the keycode of the indicated
               key as well as a mask that specifies which of the modifier keys
               are  currently  pressed.   Most  servers  set  up  this list to
               initially contain the various shift, control,  and  shift  lock
               keys on the keyboard.

       keymap table
               Applications  translate  event keycodes and modifier masks into
               keysyms using a keysym table which contains one  row  for  each
               keycode and one column for various modifier states.  This table
               is initialized by the server to correspond to normal typewriter
               conventions.    The   exact  semantics  of  how  the  table  is
               interpreted  to  produce  keysyms  depends  on  the  particular
               program,  libraries,  and  language  input method used, but the
               following conventions for the first four keysyms  in  each  row
               are generally adhered to:

       The  first  four  elements  of  the  list  are split into two groups of
       keysyms.  Group 1 contains  the  first  and  second  keysyms;  Group  2
       contains the third and fourth keysyms.  Within each group, if the first
       element is alphabetic and the the second element is the special  keysym
       NoSymbol,  then  the group is treated as equivalent to a group in which
       the first element is the lowercase letter and the second element is the
       uppercase letter.

       Switching between groups is controlled by the keysym named MODE SWITCH,
       by attaching that keysym to some key and attaching that key to any  one
       of  the  modifiers  Mod1  through  Mod5.   This  modifier is called the
       ‘‘group modifier.’’  Group 1 is used when the group  modifier  is  off,
       and Group 2 is used when the group modifier is on.

       Within a group, the modifier state determines which keysym to use.  The
       first keysym is used when the Shift and Lock modifiers  are  off.   The
       second  keysym  is  used  when  the Shift modifier is on, when the Lock
       modifier is on and the second keysym is uppercase alphabetic,  or  when
       the  Lock  modifier  is on and is interpreted as ShiftLock.  Otherwise,
       when the Lock modifier is on and is interpreted as CapsLock, the  state
       of  the Shift modifier is applied first to select a keysym; but if that
       keysym is lowercase alphabetic, then the corresponding uppercase keysym
       is used instead.


       Most  X programs attempt to use the same names for command line options
       and arguments.  All applications written with the X Toolkit  Intrinsics
       automatically accept the following options:

       -display display
               This option specifies the name of the X server to use.

       -geometry geometry
               This  option  specifies  the  initial  size and location of the

       -bg color, -background color
               Either option  specifies  the  color  to  use  for  the  window

       -bd color, -bordercolor color
               Either option specifies the color to use for the window border.

       -bw number, -borderwidth number
               Either option specifies the  width  in  pixels  of  the  window

       -fg color, -foreground color
               Either  option specifies the color to use for text or graphics.

       -fn font, -font font
               Either option specifies the font to use for displaying text.

               This option indicates that  the  user  would  prefer  that  the
               application’s  windows  initially  not  be  visible  as  if the
               windows had be  immediately  iconified  by  the  user.   Window
               managers may choose not to honor the application’s request.

               This  option  specifies  the name under which resources for the
               application should be found.  This option is  useful  in  shell
               aliases  to  distinguish between invocations of an application,
               without resorting to creating links  to  alter  the  executable
               file name.

       -rv, -reverse
               Either  option  indicates  that  the  program  should  simulate
               reverse video if possible, often by swapping the foreground and
               background colors.  Not all programs honor this or implement it
               correctly.  It is usually only used on monochrome displays.

               This option indicates that  the  program  should  not  simulate
               reverse  video.   This  is  used to override any defaults since
               reverse video doesn’t always work properly.

               This option specifies the timeout in milliseconds within  which
               two  communicating applications must respond to one another for
               a selection request.

               This option indicates that requests to the X server  should  be
               sent  synchronously,  instead  of  asynchronously.   Since Xlib
               normally  buffers  requests  to  the  server,  errors  do   not
               necessarily  get  reported  immediately after they occur.  This
               option turns off the buffering so that the application  can  be
               debugged.  It should never be used with a working program.

       -title string
               This  option  specifies  the  title to be used for this window.
               This information is sometimes  used  by  a  window  manager  to
               provide some sort of header identifying the window.

       -xnllanguage language[_territory][.codeset]
               This  option specifies the language, territory, and codeset for
               use in resolving resource and other filenames.

       -xrm resourcestring
               This option specifies a resource name and value to override any
               defaults.   It  is  also very useful for setting resources that
               don’t have explicit command line arguments.


       To make the tailoring of applications to personal preferences easier, X
       provides  a  mechanism for storing default values for program resources
       (e.g. background color, window title, etc.) that is  used  by  programs
       that  use  toolkits  based  on  the X Toolkit Intrinsics library libXt.
       (Programs using the common Gtk+ and Qt toolkits use other configuration
       mechanisms.)   Resources are specified as strings that are read in from
       various places when an application  is  run.   Program  components  are
       named  in  a  hierarchical  fashion,  with  each  node in the hierarchy
       identified by a class and an instance name.  At the top  level  is  the
       class  and instance name of the application itself.  By convention, the
       class name of the application is the same as the program name, but with
       the  first  letter  capitalized  (e.g.  Bitmap  or Emacs) although some
       programs that begin with the letter ‘‘x’’ also  capitalize  the  second
       letter for historical reasons.

       The precise syntax for resources is:

       ResourceLine      = Comment | IncludeFile | ResourceSpec | <empty line>
       Comment           = "!" {<any character except null or newline>}
       IncludeFile       = "#" WhiteSpace "include" WhiteSpace FileName WhiteSpace
       FileName          = <valid filename for operating system>
       ResourceSpec      = WhiteSpace ResourceName WhiteSpace ":" WhiteSpace Value
       ResourceName      = [Binding] {Component Binding} ComponentName
       Binding           = "." | "*"
       WhiteSpace        = {<space> | <horizontal tab>}
       Component         = "?" | ComponentName
       ComponentName     = NameChar {NameChar}
       NameChar          = "a"-"z" | "A"-"Z" | "0"-"9" | "_" | "-"
       Value             = {<any character except null or unescaped newline>}

       Elements  separated by vertical bar (|) are alternatives.  Curly braces
       ({...}) indicate zero or more repetitions  of  the  enclosed  elements.
       Square brackets ([...]) indicate that the enclosed element is optional.
       Quotes ("...") are used around literal characters.

       IncludeFile lines are  interpreted  by  replacing  the  line  with  the
       contents  of  the  specified  file.   The  word  "include"  must  be in
       lowercase.  The filename is interpreted relative to  the  directory  of
       the  file  in  which  the  line  occurs  (for  example, if the filename
       contains no directory or contains a relative directory  specification).

       If a ResourceName contains a contiguous sequence of two or more Binding
       characters, the sequence will be replaced with single "." character  if
       the  sequence contains only "." characters, otherwise the sequence will
       be replaced with a single "*" character.

       A resource database never contains more than  one  entry  for  a  given
       ResourceName.  If a resource file contains multiple lines with the same
       ResourceName, the last line in the file is used.

       Any whitespace character before  or  after  the  name  or  colon  in  a
       ResourceSpec  are  ignored.  To allow a Value to begin with whitespace,
       the two-character sequence ‘‘\space’’ (backslash followed by space)  is
       recognized  and  replaced  by  a space character, and the two-character
       sequence ‘‘\tab’’ (backslash followed by horizontal tab) is  recognized
       and  replaced  by  a  horizontal  tab  character.   To allow a Value to
       contain embedded newline characters, the two-character sequence  ‘‘\n’’
       is recognized and replaced by a newline character.  To allow a Value to
       be broken across multiple lines  in  a  text  file,  the  two-character
       sequence ‘‘\newline’’ (backslash followed by newline) is recognized and
       removed from  the  value.   To  allow  a  Value  to  contain  arbitrary
       character  codes, the four-character sequence ‘‘\nnn’’, where each n is
       a digit character in  the  range  of  ‘‘0’’-‘‘7’’,  is  recognized  and
       replaced  with a single byte that contains the octal value specified by
       the sequence.  Finally, the two-character sequence ‘‘\\’’ is recognized
       and replaced with a single backslash.

       When  an  application looks for the value of a resource, it specifies a
       complete path in the hierarchy, with both  class  and  instance  names.
       However,   resource  values  are  usually  given  with  only  partially
       specified names and classes, using  pattern  matching  constructs.   An
       asterisk  (*) is a loose binding and is used to represent any number of
       intervening components, including  none.   A  period  (.)  is  a  tight
       binding  and  is  used  to separate immediately adjacent components.  A
       question mark (?) is used to match any single component name or  class.
       A  database  entry  cannot  end in a loose binding; the final component
       (which cannot be "?") must be specified.  The lookup algorithm searches
       the  resource database for the entry that most closely matches (is most
       specific for) the full name and class being queried.   When  more  than
       one  database  entry  matches the full name and class, precedence rules
       are used to select just one.

       The full name and class are scanned from left to  right  (from  highest
       level  in  the  hierarchy to lowest), one component at a time.  At each
       level, the corresponding component  and/or  binding  of  each  matching
       entry  is  determined,  and  these matching components and bindings are
       compared according to precedence rules.  Each of the rules  is  applied
       at  each level, before moving to the next level, until a rule selects a
       single entry over all others.  The rules (in order of precedence) are:

       1.   An entry that contains a matching component (whether name,  class,
            or  "?")  takes precedence over entries that elide the level (that
            is, entries that match the level in a loose binding).

       2.   An entry with a matching name takes precedence over  both  entries
            with  a matching class and entries that match using "?".  An entry
            with a matching class takes precedence  over  entries  that  match
            using "?".

       3.   An entry preceded by a tight binding takes precedence over entries
            preceded by a loose binding.

       Programs based on the X Toolkit Intrinsics obtain  resources  from  the
       following  sources (other programs usually support some subset of these

       RESOURCE_MANAGER root window property
               Any global resources that should be available to clients on all
               machines  should  be stored in the RESOURCE_MANAGER property on
               the root window of the first screen  using  the  xrdb  program.
               This  is  frequently  taken  care  of when the user starts up X
               through the display manager or xinit.

       SCREEN_RESOURCES root window property
               Any resources specific to a given  screen  (e.g.  colors)  that
               should be available to clients on all machines should be stored
               in the SCREEN_RESOURCES property on the  root  window  of  that
               screen.  The xrdb program will sort resources automatically and
               place  them  in  RESOURCE_MANAGER   or   SCREEN_RESOURCES,   as

       application-specific files
               Directories     named     by     the    environment    variable
               XUSERFILESEARCHPATH or  the  environment  variable  XAPPLRESDIR
               (which  names  a  single directory and should end with a ’/’ on
               POSIX systems), plus directories in a standard  place  (usually
               under  /usr/share/X11/,  but  this  can  be overridden with the
               XFILESEARCHPATH environment  variable)  are  searched  for  for
               application-specific   resources.    For  example,  application
               default  resources  are  usually  kept  in  /usr/share/X11/app-
               defaults/.  See the X Toolkit Intrinsics - C Language Interface
               manual for details.

               Any user- and machine-specific resources may  be  specified  by
               setting  the XENVIRONMENT environment variable to the name of a
               resource file to  be  loaded  by  all  applications.   If  this
               variable is not defined, a file named $HOME/.Xdefaults-hostname
               is looked for instead, where hostname is the name of  the  host
               where the application is executing.

       -xrm resourcestring
               Resources  can  also  be  specified from the command line.  The
               resourcestring is a single resource name  and  value  as  shown
               above.  Note that if the string contains characters interpreted
               by the shell (e.g., asterisk), they must be quoted.  Any number
               of -xrm arguments may be given on the command line.

       Program  resources  are  organized  into groups called classes, so that
       collections  of  individual  resources  (each  of  which   are   called
       instances) can be set all at once.  By convention, the instance name of
       a resource begins with a lowercase letter and class name with an  upper
       case  letter.   Multiple word resources are concatenated with the first
       letter of the succeeding words capitalized.  Applications written  with
       the X Toolkit Intrinsics will have at least the following resources:

       background (class Background)
               This  resource  specifies  the  color  to  use  for  the window

       borderWidth (class BorderWidth)
               This resource specifies the  width  in  pixels  of  the  window

       borderColor (class BorderColor)
               This resource specifies the color to use for the window border.

       Most applications using the X Toolkit Intrinsics also have the resource
       foreground (class Foreground), specifying the color to use for text and
       graphics within the window.

       By combining class and instance specifications, application preferences
       can be set quickly and easily.  Users of color displays will frequently
       want to set Background and Foreground classes to  particular  defaults.
       Specific  color  instances  such as text cursors can then be overridden
       without having to define all of the related resources.  For example,

           bitmap*Dashed:  off
           XTerm*cursorColor:  gold
           XTerm*multiScroll:  on
           XTerm*jumpScroll:  on
           XTerm*reverseWrap:  on
           XTerm*curses:  on
           XTerm*Font:  6x10
           XTerm*scrollBar: on
           XTerm*scrollbar*thickness: 5
           XTerm*multiClickTime: 500
           XTerm*charClass:  33:48,37:48,45-47:48,64:48
           XTerm*cutNewline: off
           XTerm*cutToBeginningOfLine: off
           XTerm*titeInhibit:  on
           XTerm*ttyModes:  intr ^c erase ^? kill ^u
           XLoad*Background: gold
           XLoad*Foreground: red
           XLoad*highlight: black
           XLoad*borderWidth: 0
           emacs*Geometry:  80x65-0-0
           emacs*Background:  rgb:5b/76/86
           emacs*Foreground:  white
           emacs*Cursor:  white
           emacs*BorderColor:  white
           emacs*Font:  6x10
           xmag*geometry: -0-0
           xmag*borderColor:  white

       If these resources were stored in a file  called  .Xresources  in  your
       home  directory,  they  could be added to any existing resources in the
       server with the following command:

           % xrdb -merge $HOME/.Xresources

       This is  frequently  how  user-friendly  startup  scripts  merge  user-
       specific   defaults   into  any  site-wide  defaults.   All  sites  are
       encouraged  to  set  up  convenient  ways  of   automatically   loading
       resources.  See  the Xlib manual section Resource Manager Functions for
       more information.


              This is the only mandatory environment variable. It  must  point
              to an X server. See section "Display Names" above.

              This  must point to a file that contains authorization data. The
              default  is  $HOME/.Xauthority.  See   Xsecurity(7),   xauth(1),
              xdm(1), Xau(3).

              This  must point to a file that contains authorization data. The
              default is $HOME/.ICEauthority.

              The first non-empty  value  among  these  three  determines  the
              current locale’s facet for character handling, and in particular
              the  default  text  encoding.   See   locale(7),   setlocale(3),

              This  variable  can  be  set  to  contain additional information
              important for the  current  locale  setting.  Typically  set  to
              @im=<input-method>  to  enable  a  particular  input method. See

              This must point to a directory containing the locale.alias  file
              and Compose and XLC_LOCALE file hierarchies for all locales. The
              default value is /usr/share/X11/locale.

              This must point to a file containing X resources. The default is
              $HOME/.Xdefaults-<hostname>.  Unlike  $HOME/.Xresources,  it  is
              consulted each time an X application starts.

              This must contain a colon  separated  list  of  path  templates,
              where  libXt  will  search for resource files. The default value
              consists of


              A path template is transformed to a pathname by substituting:

                  %D => the implementation-specific default path
                  %N => name (basename) being searched for
                  %T => type (dirname) being searched for
                  %S => suffix being searched for
                  %C => value of the resource "customization"
                        (class "Customization")
                  %L => the locale name
                  %l => the locale’s language (part before ’_’)
                  %t => the locale’s territory (part after ’_‘ but before ’.’)
                  %c => the locale’s encoding (part after ’.’)

              This must contain a colon  separated  list  of  path  templates,
              where  libXt  will search for user dependent resource files. The
              default value is:


              $XAPPLRESDIR defaults to $HOME, see below.

              A path template is transformed to a pathname by substituting:

                  %D => the implementation-specific default path
                  %N => name (basename) being searched for
                  %T => type (dirname) being searched for
                  %S => suffix being searched for
                  %C => value of the resource "customization"
                        (class "Customization")
                  %L => the locale name
                  %l => the locale’s language (part before ’_’)
                  %t => the locale’s territory (part after ’_‘ but before ’.’)
                  %c => the locale’s encoding (part after ’.’)

              This must point to a base directory where the  user  stores  his
              application  dependent  resource  files.  The  default  value is
              $HOME. Only used if XUSERFILESEARCHPATH is not set.

              This  must  point  to  a  file  containing  nonstandard   keysym
              definitions.  The default value is /usr/share/X11/XKeysymDB.

       XCMSDB This must point to a color name database file. The default value

              This serves as main identifier for resources  belonging  to  the
              program  being executed. It defaults to the basename of pathname
              of the program.

              Denotes the session manager  to  which  the  application  should
              connect. See xsm(1), rstart(1).

              Setting   this  variable  to  a  non-empty  value  disables  the
              XFree86-Bigfont extension. This  extension  is  a  mechanism  to
              reduce  the  memory  consumption  of  big fonts by use of shared


       These variables influence the X Keyboard Extension.


       The following is a collection of sample command lines for some  of  the
       more  frequently  used  commands.  For more information on a particular
       command, please refer to that command’s manual page.

           %  xrdb $HOME/.Xresources
           %  xmodmap -e "keysym BackSpace = Delete"
           %  mkfontdir /usr/local/lib/X11/otherfonts
           %  xset fp+ /usr/local/lib/X11/otherfonts
           %  xmodmap $HOME/
           %  xsetroot -solid ’rgbi:.8/.8/.8’
           %  xset b 100 400 c 50 s 1800 r on
           %  xset q
           %  twm
           %  xmag
           %  xclock -geometry 48x48-0+0 -bg blue -fg white
           %  xeyes -geometry 48x48-48+0
           %  xbiff -update 20
           %  xlsfonts ’*helvetica*’
           %  xwininfo -root
           %  xdpyinfo -display joesworkstation:0
           %  xhost -joesworkstation
           %  xrefresh
           %  xwd | xwud
           %  bitmap 32x32
           %  xcalc -bg blue -fg magenta
           %  xterm -geometry 80x66-0-0 -name myxterm $*


       A wide variety of error messages are generated from  various  programs.
       The  default  error  handler  in Xlib (also used by many toolkits) uses
       standard resources to construct diagnostic messages when errors  occur.
       The    defaults    for   these   messages   are   usually   stored   in
       usr/share/X11/XErrorDB.  If this file is not  present,  error  messages
       will be rather terse and cryptic.

       When  the  X  Toolkit  Intrinsics  encounter errors converting resource
       strings to the appropriate  internal  format,  no  error  messages  are
       usually  printed.   This is convenient when it is desirable to have one
       set  of  resources  across  a  variety  of  displays  (e.g.  color  vs.
       monochrome,  lots  of  fonts  vs. very few, etc.), although it can pose
       problems for trying to determine why an application might  be  failing.
       This    behavior    can    be    overridden    by   the   setting   the
       StringConversionWarnings resource.

       To force the X Toolkit Intrinsics to  always  print  string  conversion
       error  messages,  the  following  resource should be placed in the file
       that gets loaded onto the  RESOURCE_MANAGER  property  using  the  xrdb
       program  (frequently  called  .Xresources  or  .Xres in the user’s home

           *StringConversionWarnings: on

       To have conversion messages printed for just a particular  application,
       the appropriate instance name can be placed before the asterisk:

           xterm*StringConversionWarnings: on


       XOrgFoundation(7), XStandards(7), Xsecurity(7), appres(1), bdftopcf(1),
       bitmap(1), editres(1), fsinfo(1), fslsfonts(1), fstobdf(1), iceauth(1),
       imake(1), makedepend(1), mkfontdir(1), oclock(1), proxymngr(1), rgb(1),
       resize(1), rstart(1), smproxy(1), twm(1),  x11perf(1),  x11perfcomp(1),
       xauth(1),  xclipboard(1),  xclock(1),  xcmsdb(1),  xconsole(1), xdm(1),
       xdpyinfo(1),  xfd(1),   xfindproxy(1),   xfs(1),   xfwp(1),   xhost(1),
       xinit(1),  xkbbell(1), xkbcomp(1), xkbevd(1), xkbprint(1), xkbvleds(1),
       xkbwatch(1),   xkill(1),    xlogo(1),    xlsatoms(1),    xlsclients(1),
       xlsfonts(1),    xmag(1),   xmh(1),   xmodmap(1),   xprop(1),   xrdb(1),
       xrefresh(1),  xrx(1),  xset(1),   xsetroot(1),   xsm(1),   xstdcmap(1),
       xterm(1),  xwd(1), xwininfo(1), xwud(1).  Xserver(1), Xorg(1), Xdmx(1),
       Xephyr(1), Xnest(1), Xquartz(1), Xvfb(1), Xvnc(1), XWin(1).  Xlib  -  C
       Language X Interface, and X Toolkit Intrinsics - C Language Interface


       X Window System is a trademark of The Open Group.


       A  cast of thousands, literally.  Releases 6.7 and later are brought to
       you by the X.Org Foundation. The names of all  people  who  made  it  a
       reality will be found in the individual documents and source files.

       Releases  6.6  and  6.5  were done by The X.Org Group.  Release 6.4 was
       done by The X Project Team.  The Release 6.3 distribution was from  The
       X  Consortium,  Inc.  The staff members at the X Consortium responsible
       for that  release  were:  Donna  Converse  (emeritus),  Stephen  Gildea
       (emeritus),   Kaleb   Keithley,   Matt  Landau  (emeritus),  Ralph  Mor
       (emeritus), Janet O’Halloran, Bob Scheifler, Ralph Swick, Dave  Wiggins
       (emeritus), and Reed Augliere.

       The X Window System standard was originally developed at the Laboratory
       for Computer Science at the Massachusetts Institute of Technology,  and
       all  rights  thereto  were  assigned  to the X Consortium on January 1,
       1994.  X Consortium, Inc. closed its doors on December 31,  1996.   All
       rights to the X Window System have been assigned to The Open Group.