xrdb - X server resource database utility
xrdb [-option ...] [filename]
Xrdb is used to get or set the contents of the RESOURCE_MANAGER property
  on the root window of screen 0, or the SCREEN_RESOURCES property on the root
  window of any or all screens, or everything combined. You would normally run
  this program from your X startup file.
Most X clients use the RESOURCE_MANAGER and SCREEN_RESOURCES
    properties to get user preferences about color, fonts, and so on for
    applications. Having this information in the server (where it is available
    to all clients) instead of on disk, solves the problem in previous versions
    of X that required you to maintain defaults files on every machine
    that you might use. It also allows for dynamic changing of defaults without
    editing files.
The RESOURCE_MANAGER property is used for resources that apply to
    all screens of the display. The SCREEN_RESOURCES property on each screen
    specifies additional (or overriding) resources to be used for that screen.
    (When there is only one screen, SCREEN_RESOURCES is normally not used, all
    resources are just placed in the RESOURCE_MANAGER property.)
The file specified by filename (or the contents from
    standard input if - or no filename is given) is optionally passed through
    the C preprocessor with the following symbols defined, based on the
    capabilities of the server being used:
  - SERVERHOST=hostname
- the hostname portion of the display to which you are connected.
- SRVR_name
- the SERVERHOST hostname string turned into a legal identifier. For
      example, "my-dpy.lcs.mit.edu" becomes
    SRVR_my_dpy_lcs_mit_edu.
- HOST=hostname
- the same as SERVERHOST.
- DISPLAY_NUM=num
- the number of the display on the server host.
- CLIENTHOST=hostname
- the name of the host on which xrdb is running.
- CLNT_name
- the CLIENTHOST hostname string turned into a legal identifier. For
      example, "expo.lcs.mit.edu" becomes CLNT_expo_lcs_mit_edu.
- RELEASE=num
- the vendor release number for the server. The interpretation of this
      number will vary depending on VENDOR.
- REVISION=num
- the X protocol minor version supported by this server (currently 0).
- VERSION=num
- the X protocol major version supported by this server (should always be
      11).
- VENDOR="vendor"
- a string literal specifying the vendor of the server.
- VNDR_name
- the VENDOR name string turned into a legal identifier. For example,
      "MIT X Consortium" becomes VNDR_MIT_X_Consortium.
- EXT_name
- A symbol is defined for each protocol extension supported by the server.
      Each extension string name is turned into a legal identifier. For example,
      "X3D-PEX" becomes EXT_X3D_PEX.
- NUM_SCREENS=num
- the total number of screens.
- SCREEN_NUM=num
- the number of the current screen (from zero).
- BITS_PER_RGB=num
- the number of significant bits in an RGB color specification. This is the
      log base 2 of the number of distinct shades of each primary that the
      hardware can generate. Note that it usually is not related to PLANES.
- CLASS=visualclass
- one of StaticGray, GrayScale, StaticColor, PseudoColor, TrueColor,
      DirectColor. This is the visual class of the root window.
- CLASS_visualclass=visualid
- the visual class of the root window in a form you can #ifdef on.
      The value is the numeric id of the visual.
- COLOR
- defined only if CLASS is one of StaticColor, PseudoColor, TrueColor, or
      DirectColor.
- CLASS_visualclass_depth=num
- A symbol is defined for each visual supported for the screen. The symbol
      includes the class of the visual and its depth; the value is the numeric
      id of the visual. (If more than one visual has the same class and depth,
      the numeric id of the first one reported by the server is used.)
- HEIGHT=num
- the height of the root window in pixels.
- WIDTH=num
- the width of the root window in pixels.
- PLANES=num
- the number of bit planes (the depth) of the root window.
- X_RESOLUTION=num
- the x resolution of the screen in pixels per meter.
- Y_RESOLUTION=num
- the y resolution of the screen in pixels per meter.
SRVR_name, CLNT_name, VNDR_name, and
    EXT_name identifiers are formed by changing all characters other than
    letters and digits into underscores (_).
Lines that begin with an exclamation mark (!) are ignored and may
    be used as comments.
Note that since xrdb can read from standard input, it can
    be used to the change the contents of properties directly from a terminal or
    from a shell script.
xrdb program accepts the following options:
  - -help
- This option (or any unsupported option) will cause a brief description of
      the allowable options and parameters to be printed.
- -version
- This option will cause the xrdb version to be printed and the program to
      exit without performing any other operations.
- -display display
- This option specifies the X server to be used; see X(7). It also
      specifies the screen to use for the -screen option, and it
      specifies the screen from which preprocessor symbols are derived for the
      -global option.
- -all
- This option indicates that operation should be performed on the
      screen-independent resource property (RESOURCE_MANAGER), as well as the
      screen-specific property (SCREEN_RESOURCES) on every screen of the
      display. For example, when used in conjunction with -query, the
      contents of all properties are output. For -load, -override
      and -merge, the input file is processed once for each screen. The
      resources which occur in common in the output for every screen are
      collected, and these are applied as the screen-independent resources. The
      remaining resources are applied for each individual per-screen property.
      This the default mode of operation.
- -global
- This option indicates that the operation should only be performed on the
      screen-independent RESOURCE_MANAGER property.
- -screen
- This option indicates that the operation should only be performed on the
      SCREEN_RESOURCES property of the default screen of the display.
- -screens
- This option indicates that the operation should be performed on the
      SCREEN_RESOURCES property of each screen of the display. For -load,
      -override and -merge, the input file is processed for each
      screen.
- -n
- This option indicates that changes to the specified properties (when used
      with -load, -override or -merge) or to the resource
      file (when used with -edit) should be shown on the standard output,
      but should not be performed.
- -quiet
- This option indicates that warning about duplicate entries should not be
      displayed.
- -cpp filename
- This option specifies the pathname of the C preprocessor program to be
      used. Although xrdb was designed to use CPP, any program that acts
      as a filter and accepts the -D, -I, and -U options may be used.
- -nocpp
- This option indicates that xrdb should not run the input file
      through a preprocessor before loading it into properties.
- -undef
- This option is passed to the C preprocessor if used. It prevents it from
      predefining any system specific macros.
- -E
- This option indicates that any cpp command run and the output from it
      should be shown on standard output. If -nocpp was also specified,
      the input file will be shown as read. The specified changes will also be
      performed unless the -n option is also specified.
- -symbols
- This option indicates that the symbols that are defined for the
      preprocessor should be printed onto the standard output.
- -query
- This option indicates that the current contents of the specified
      properties should be printed onto the standard output. Note that since
      preprocessor commands in the input resource file are part of the input
      file, not part of the property, they won't appear in the output from this
      option. The -edit option can be used to merge the contents of
      properties back into the input resource file without damaging preprocessor
      commands.
- -get name
- This option indicates that the current content of the property matching
      name should be printed onto the standard output.
- -load
- This option indicates that the input should be loaded as the new value of
      the specified properties, replacing whatever was there (i.e. the old
      contents are removed). This is the default action.
- -override
- This option indicates that the input should be added to, instead of
      replacing, the current contents of the specified properties. New entries
      override previous entries.
- -merge
- This option indicates that the input should be merged and
      lexicographically sorted with, instead of replacing, the current contents
      of the specified properties.
- -remove
- This option indicates that the specified properties should be removed from
      the server.
- -retain
- This option indicates that the server should be instructed not to reset if
      xrdb is the first client. This should never be necessary under
      normal conditions, since xdm and xinit always act as the
      first client.
- -edit filename
- This option indicates that the contents of the specified properties should
      be edited into the given file, replacing any values already listed there.
      This allows you to put changes that you have made to your defaults back
      into your resource file, preserving any comments or preprocessor
    lines.
- -backup string
- This option specifies a suffix to be appended to the filename used with
      -edit to generate a backup file.
- -Dname[=value]
- This option is passed through to the preprocessor and is used to define
      symbols for use with conditionals such as #ifdef.
- -Uname
- This option is passed through to the preprocessor and is used to remove
      any definitions of this symbol.
- -Idirectory
- This option is passed through to the preprocessor and is used to specify a
      directory to search for files that are referenced with
    #include.
Xrdb does not load any files on its own, but many desktop environments
  use xrdb to load ~/.Xresources files on session startup to initialize
  the resource database, as a generalized replacement for ~/.Xdefaults
  files.
X(7), appres(1), listres(1), Xlib Resource Manager documentation, Xt resource
  documentation
  - DISPLAY
- to figure out which display to use.
The default for no arguments should be to query, not to overwrite, so that it is
  consistent with other programs.
Bob Scheifler, Phil Karlton, rewritten from the original by Jim Gettys