xprop



XPROP(1)                                                              XPROP(1)




NAME

       xprop - property displayer for X


SYNOPSIS

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


SUMMARY

       The xprop utility is for displaying window and font properties in an  X
       server.   One  window  or font is selected using the command line argu-
       ments 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.


OPTIONS

       -help   Print out a summary of command line options.


       -grammar
               Print out a detailed grammar for all command line options.


       -id id  This argument allows the user to select window id on  the  com-
               mand  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 appli-
               cation.


       -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 win-
               dow.   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(7x).


       -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  dis-
               played.


       -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  indi-
               cated 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
               events.


       -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.


DESCRIPTION

       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
       printed.

       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 win-
       dow, the -font argument must be used.

       Other than the above four arguments and the -help argument for  obtain-
       ing  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
       displayed.

       The following paragraphs describe how to construct  formats  and  dfor-
       mats.   However,  for  the vast majority of users and uses, this should
       not be necessary as the built in defaults contain the formats and dfor-
       mats  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 mean-
       ing use the field size information associated with the property itself.
       (This is only needed for special cases like type INTEGER which is actu-
       ally  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 origi-
       nally  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.

       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.

       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 exam-
       ple, 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 num-
       ber 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 dis-
       play  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 state-
       ment.   ?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 repre-
       sents  the constant value n while $n represents the value of field num-
       ber n.  mn is 1 if flag number n in the first field having format char-
       acter ’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
       boolean.

       In order to display a property, xprop needs both a format and  a  dfor-
       mat.   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 for-
       mats 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 for-
       mats.

       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, for-
       mat 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.


EXAMPLES

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

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

       To  display  the  start  of  the  cut  buffer:  xprop  -root  -len  100
       CUT_BUFFER0

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

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


ENVIRONMENT

       DISPLAY To get default display.

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



SEE ALSO

       X(7x), xwininfo(1)


AUTHOR

       Mark Lillibridge, MIT Project Athena



X.Org                            Version 6.8.2                        XPROP(1)

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