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XPROP(1)							      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	 prop-
       erty-name]  [-set  property-name	 value]	 [-spy]	[-f atom format	[dfor-
       mat]]* [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 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

       -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  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-

       -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(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  dis-

       -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

       -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 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 format-
       ting 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

       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.

       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	viola-
	      tion 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 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

       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-

       The  format of the files	referred to by the -fs argument	and the	XPROP-
       FORMATS 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.

       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	1.2.2			      XPROP(1)


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