Provided by: x11-utils_7.7+3_i386 bug


       xprop - property displayer for X


       xprop  [-help] [-grammar] [-id id] [-root] [-name name] [-frame] [-font
       font]  [-display  display]  [-len  n]  [-notype]  [-fs  file]  [-remove
       property-name]  [-set  property-name  value]  [-spy]  [-f  atom  format
       [dformat]]* [format [dformat] atom]*


       The xprop utility is for displaying window and font properties in an  X
       server.   One  window  or  font  is  selected  using  the  command line
       arguments or possibly in the case of  a  window,  by  clicking  on  the
       desired  window.   A  list  of  properties is then given, possibly with
       formatting information.


       -help   Print out a summary of command line options.

               Print out a detailed grammar for all command line options.

       -id id  This argument allows the  user  to  select  window  id  on  the
               command line rather than using the pointer to select the target
               window.  This is very useful in debugging X applications  where
               the  target window is not mapped to the screen or where the use
               of the pointer  might  be  impossible  or  interfere  with  the

       -name name
               This  argument allows the user to specify that the window named
               name is the target window on the command line rather than using
               the pointer to select the target window.

       -font font
               This argument allows the user to specify that the properties of
               font font should be displayed.

       -root   This argument specifies that X's  root  window  is  the  target
               window.   This is useful in situations where the root window is
               completely obscured.

       -display display
               This argument allows you to specify the server to  connect  to;
               see X(7).

       -len n  Specifies  that  at most n bytes of any property should be read
               or displayed.

       -notype Specifies  that  the  type  of  each  property  should  not  be

       -fs file
               Specifies  that  file  file  should be used as a source of more
               formats for properties.

       -frame  Specifies that when selecting a window by hand (i.e. if none of
               -name,  -root,  or  -id  are given), look at the window manager
               frame (if any) instead of looking for the client window.

       -remove property-name
               Specifies the name  of  a  property  to  be  removed  from  the
               indicated window.

       -set property-name value
               Specifies  the  name  of a property and a property value, to be
               set on the indicated window.

       -spy    Examine window properties forever, looking for property  change

       -f name format [dformat]
               Specifies  that  the  format for name should be format and that
               the dformat for name should be dformat.  If dformat is missing,
               " = $0+\n" is assumed.


       For  each of these properties, its value on the selected window or font
       is printed using the supplied formatting information  if  any.   If  no
       formatting  information  is supplied, internal defaults are used.  If a
       property is not defined on the selected window or font,  "not  defined"
       is  printed  as  the  value  for that property.  If no property list is
       given, all the properties possessed by the selected window or font  are

       A  window  may  be selected in one of four ways.  First, if the desired
       window is the root window, the -root argument  may  be  used.   If  the
       desired  window  is not the root window, it may be selected in two ways
       on the command line, either by id number such as might be obtained from
       xwininfo,  or by name if the window possesses a name.  The -id argument
       selects a window by id number in either decimal or hex (must start with
       0x) while the -name argument selects a window by name.

       The  last  way  to select a window does not involve the command line at
       all.  If none  of  -font,  -id,  -name,  and  -root  are  specified,  a
       crosshairs  cursor  is  displayed and the user is allowed to choose any
       visible window by pressing any pointer button in  the  desired  window.
       If  it  is  desired  to  display  properties  of a font as opposed to a
       window, the -font argument must be used.

       Other than  the  above  four  arguments  and  the  -help  argument  for
       obtaining  help, and the -grammar argument for listing the full grammar
       for the command line, all the other command line arguments are used  in
       specifying both the format of the properties to be displayed and how to
       display them.  The -len n argument specifies that at most  n  bytes  of
       any  given  property  will  be  read and displayed.  This is useful for
       example when displaying the cut buffer on the root window  which  could
       run to several pages if displayed in full.

       Normally each property name is displayed by printing first the property
       name then its type (if it has  one)  in  parentheses  followed  by  its
       value.   The  -notype argument specifies that property types should not
       be displayed.  The -fs argument is used to specify a file containing  a
       list of formats for properties while the -f argument is used to specify
       the format for one property.

       The formatting information for a  property  actually  consists  of  two
       parts,  a  format  and  a  dformat.   The  format  specifies the actual
       formatting of the property (i.e., is it made up  of  words,  bytes,  or
       longs?,  etc.)  while  the dformat specifies how the property should be

       The  following  paragraphs  describe  how  to  construct  formats   and
       dformats.   However,  for  the  vast  majority  of users and uses, this
       should not be necessary as the built in defaults  contain  the  formats
       and  dformats  necessary  to  display  all the standard properties.  It
       should only be necessary to specify  formats  and  dformats  if  a  new
       property  is being dealt with or the user dislikes the standard display
       format.  New users especially are encouraged to skip this part.

       A format consists of one of 0, 8, 16, or 32 followed by a  sequence  of
       one  or more format characters.  The 0, 8, 16, or 32 specifies how many
       bits per field there are in the  property.   Zero  is  a  special  case
       meaning  use  the  field  size information associated with the property
       itself.  (This is only needed for special cases like type INTEGER which
       is  actually  three different types depending on the size of the fields
       of the property.)

       A value of 8 means that the property is a sequence  of  bytes  while  a
       value  of  16 would mean that the property is a sequence of words.  The
       difference between these two lies in the  fact  that  the  sequence  of
       words will be byte swapped while the sequence of bytes will not be when
       read by a machine of the  opposite  byte  order  of  the  machine  that
       originally  wrote the property.  For more information on how properties
       are formatted and stored, consult the Xlib manual.

       Once the size of the fields has been  specified,  it  is  necessary  to
       specify  the  type  of each field (i.e., is it an integer, a string, an
       atom, or what?)  This is done using one format character per field.  If
       there  are more fields in the property than format characters supplied,
       the last character will be repeated as many times as necessary for  the
       extra fields.  The format characters and their meaning are as follows:

       a      The  field holds an atom number.  A field of this type should be
              of size 32.

       b      The field is an boolean.  A 0 means false  while  anything  else
              means true.

       c      The field is an unsigned number, a cardinal.

       i      The field is a signed integer.

       m      The field is a set of bit flags, 1 meaning on.

       o      The  field  is an array of icons, packed as a sequence of 32 bit
              numbers consisting of the width, height and ARGB  pixel  values,
              as  defined for the _NET_WM_ICON property in the Extended Window
              Manager Hints specification.   A field of this type must  be  of
              size 32.

       s      This  field and the next ones until either a 0 or the end of the
              property represent a sequence of bytes.  This  format  character
              is  only usable with a field size of 8 and is most often used to
              represent a string.

       t      This field and the next ones until either a 0 or the end of  the
              property represent an internationalized text string. This format
              character is only usable with a field size of 8. The  string  is
              assumed to be in an ICCCM compliant encoding and is converted to
              the current locale encoding before being output.

       u      This field and the next ones until either a 0 or the end of  the
              property  represent an UTF-8 encoded unicode string. This format
              character is only usable with a field size of 8. If  the  string
              is  found  to  be  an  invalid  character,  the type of encoding
              violation is printed instead, followed by the  string  formatted
              using  's'.  When  in  an  environment not capable of displaying
              UTF-8 encoded string, behaviour is identical to 's'.

       x      The field is a hex number (like 'c' but displayed in hex -  most
              useful for displaying window ids and the like)

       An  example format is 32ica which is the format for a property of three
       fields of 32 bits each, the first holding a signed integer, the  second
       an unsigned integer, and the third an atom.

       The  format  of a dformat unlike that of a format is not so rigid.  The
       only limitations on a dformat is that one may not start with  a  letter
       or  a  dash.   This  is so that it can be distinguished from a property
       name or an argument.  A dformat is a  text  string  containing  special
       characters instructing that various fields be printed at various points
       in a manner similar to the  formatting  string  used  by  printf.   For
       example,  the  dformat " is ( $0, $1 \)\n" would render the POINT 3, -4
       which has a format of 32ii as " is ( 3, -4 )\n".

       Any character other than a $, ?, \, or a  (  in  a  dformat  prints  as
       itself.   To  print  out  one  of $, ?, \, or ( precede it by a \.  For
       example, to print out a $, use \$.  Several special backslash sequences
       are  provided  as  shortcuts.   \n will cause a newline to be displayed
       while \t will cause a tab to be displayed.  \o  where  o  is  an  octal
       number will display character number o.

       A  $ followed by a number n causes field number n to be displayed.  The
       format of the displayed field depends on the formatting character  used
       to  describe  it  in  the corresponding format.  I.e., if a cardinal is
       described by 'c' it will print in decimal while if it is described by a
       'x' it is displayed in hex.

       If the field is not present in the property (this is possible with some
       properties), <field not available>  is  displayed  instead.   $n+  will
       display  field number n then a comma then field number n+1 then another
       comma then ... until the  last  field  defined.   If  field  n  is  not
       defined, nothing is displayed.  This is useful for a property that is a
       list of values.

       A ? is used to start  a  conditional  expression,  a  kind  of  if-then
       statement.   ?exp(text)  will display text if and only if exp evaluates
       to non-zero.  This is useful for two things.  First, it  allows  fields
       to  be displayed if and only if a flag is set.  And second, it allows a
       value such as a state number to be displayed as a name rather  than  as
       just a number.  The syntax of exp is as follows:

       exp    ::= term | term=exp | !exp

       term   ::= n | $n | mn

       The  !  operator is a logical ``not'', changing 0 to 1 and any non-zero
       value to 0.  = is an  equality  operator.   Note  that  internally  all
       expressions  are  evaluated  as  32  bit  numbers so -1 is not equal to
       65535.  = returns 1 if the two values  are  equal  and  0  if  not.   n
       represents  the constant value n while $n represents the value of field
       number n.  mn is 1 if flag number n in the first  field  having  format
       character 'm' in the corresponding format is 1, 0 otherwise.

       Examples:  ?m3(count:  $3\n)  displays field 3 with a label of count if
       and  only  if  flag  number   3   (count   starts   at   0!)   is   on.
       ?$2=0(True)?!$2=0(False)  displays  the  inverted value of field 2 as a

       In order to display a  property,  xprop  needs  both  a  format  and  a
       dformat.  Before xprop uses its default values of a format of 32x and a
       dformat of " = { $0+ }\n", it searches several places in an attempt  to
       find  more specific formats.  First, a search is made using the name of
       the property.  If this fails, a search is made using the  type  of  the
       property.   This  allows  type  STRING  to  be  defined with one set of
       formats while allowing property WM_NAME which is of type STRING  to  be
       defined  with a different format.  In this way, the display formats for
       a given type can be overridden for specific properties.

       The locations searched are in order: the format if any  specified  with
       the property name (as in 8x WM_NAME), the formats defined by -f options
       in last to first order, the contents of the file specified by  the  -fs
       option  if any, the contents of the file specified by the environmental
       variable XPROPFORMATS if any, and finally  xprop's  built  in  file  of

       The  format  of  the  files  referred  to  by  the -fs argument and the
       XPROPFORMATS variable is one or more lines of the following form:

       name format [dformat]

       Where name is either the name of a property or  the  name  of  a  type,
       format is the format to be used with name and dformat is the dformat to
       be used with name.  If dformat is not present, " = $0+\n" is assumed.


       To display the name of the root window: xprop -root WM_NAME

       To display the window manager hints for the clock: xprop  -name  xclock

       To  display  the  start  of  the  cut  buffer:  xprop  -root  -len  100

       To display the  point  size  of  the  fixed  font:  xprop  -font  fixed

       To display all the properties of window # 0x200007: xprop -id 0x200007

       To  set  a  simple string property: xprop -root -format MY_ATOM_NAME 8s
       -set MY_ATOM_NAME  "my_value"


       DISPLAY To get default display.

               Specifies the name of a file from which additional formats  are
               to be obtained.


       X(7), xdpyinfo(1), xwininfo(1), xdriinfo(1), glxinfo(1), xvinfo(1)


       Mark Lillibridge, MIT Project Athena