XPROP(1)                    General Commands Manual                   XPROP(1)

       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] [-version] [-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

               Print program version information and exit.

       -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

X Version 11                      xprop 1.2.4                         XPROP(1)