1XPROP(1) General Commands Manual XPROP(1)
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6 xprop - property displayer for X
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9 xprop [-help] [-grammar] [-id id] [-root] [-name name] [-frame] [-font
10 font] [-display display] [-len n] [-notype] [-fs file] [-remove prop‐
11 erty-name] [-set property-name value] [-spy] [-f atom format [dfor‐
12 mat]]* [format [dformat] atom]*
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15 The xprop utility is for displaying window and font properties in an X
16 server. One window or font is selected using the command line argu‐
17 ments or possibly in the case of a window, by clicking on the desired
18 window. A list of properties is then given, possibly with formatting
19 information.
20
22 -help Print out a summary of command line options.
23 -grammar
25 Print out a detailed grammar for all command line options.
26 -id id This argument allows the user to select window id on the com‐
28 mand line rather than using the pointer to select the target
29 window. This is very useful in debugging X applications where
30 the target window is not mapped to the screen or where the use
31 of the pointer might be impossible or interfere with the appli‐
32 cation.
33 -name name
35 This argument allows the user to specify that the window named
36 name is the target window on the command line rather than using
37 the pointer to select the target window.
38 -font font
40 This argument allows the user to specify that the properties of
41 font font should be displayed.
42 -root This argument specifies that X's root window is the target win‐
44 dow. This is useful in situations where the root window is
45 completely obscured.
46 -display display
48 This argument allows you to specify the server to connect to;
49 see X(7).
50 -len n Specifies that at most n bytes of any property should be read
52 or displayed.
53 -notype Specifies that the type of each property should not be dis‐
55 played.
56 -fs file
58 Specifies that file file should be used as a source of more
59 formats for properties.
60 -frame Specifies that when selecting a window by hand (i.e. if none of
62 -name, -root, or -id are given), look at the window manager
63 frame (if any) instead of looking for the client window.
64 -remove property-name
66 Specifies the name of a property to be removed from the indi‐
67 cated window.
68 -set property-name value
70 Specifies the name of a property and a property value, to be
71 set on the indicated window.
72 -spy Examine window properties forever, looking for property change
74 events.
75 -f name format [dformat]
77 Specifies that the format for name should be format and that
78 the dformat for name should be dformat. If dformat is missing,
79 " = $0+\n" is assumed.
80
82 For each of these properties, its value on the selected window or font
83 is printed using the supplied formatting information if any. If no
84 formatting information is supplied, internal defaults are used. If a
85 property is not defined on the selected window or font, "not defined"
86 is printed as the value for that property. If no property list is
87 given, all the properties possessed by the selected window or font are
88 printed.
89 A window may be selected in one of four ways. First, if the desired
91 window is the root window, the -root argument may be used. If the
92 desired window is not the root window, it may be selected in two ways
93 on the command line, either by id number such as might be obtained from
94 xwininfo, or by name if the window possesses a name. The -id argument
95 selects a window by id number in either decimal or hex (must start with
96 0x) while the -name argument selects a window by name.
97 The last way to select a window does not involve the command line at
99 all. If none of -font, -id, -name, and -root are specified, a
100 crosshairs cursor is displayed and the user is allowed to choose any
101 visible window by pressing any pointer button in the desired window.
102 If it is desired to display properties of a font as opposed to a win‐
103 dow, the -font argument must be used.
104 Other than the above four arguments and the -help argument for obtain‐
106 ing help, and the -grammar argument for listing the full grammar for
107 the command line, all the other command line arguments are used in
108 specifying both the format of the properties to be displayed and how to
109 display them. The -len n argument specifies that at most n bytes of
110 any given property will be read and displayed. This is useful for
111 example when displaying the cut buffer on the root window which could
112 run to several pages if displayed in full.
113 Normally each property name is displayed by printing first the property
115 name then its type (if it has one) in parentheses followed by its
116 value. The -notype argument specifies that property types should not
117 be displayed. The -fs argument is used to specify a file containing a
118 list of formats for properties while the -f argument is used to specify
119 the format for one property.
120 The formatting information for a property actually consists of two
122 parts, a format and a dformat. The format specifies the actual format‐
123 ting of the property (i.e., is it made up of words, bytes, or longs?,
124 etc.) while the dformat specifies how the property should be displayed.
125 The following paragraphs describe how to construct formats and dfor‐
127 mats. However, for the vast majority of users and uses, this should
128 not be necessary as the built in defaults contain the formats and dfor‐
129 mats necessary to display all the standard properties. It should only
130 be necessary to specify formats and dformats if a new property is being
131 dealt with or the user dislikes the standard display format. New users
132 especially are encouraged to skip this part.
133 A format consists of one of 0, 8, 16, or 32 followed by a sequence of
135 one or more format characters. The 0, 8, 16, or 32 specifies how many
136 bits per field there are in the property. Zero is a special case mean‐
137 ing use the field size information associated with the property itself.
138 (This is only needed for special cases like type INTEGER which is actu‐
139 ally three different types depending on the size of the fields of the
140 property.)
141 A value of 8 means that the property is a sequence of bytes while a
143 value of 16 would mean that the property is a sequence of words. The
144 difference between these two lies in the fact that the sequence of
145 words will be byte swapped while the sequence of bytes will not be when
146 read by a machine of the opposite byte order of the machine that origi‐
147 nally wrote the property. For more information on how properties are
148 formatted and stored, consult the Xlib manual.
149 Once the size of the fields has been specified, it is necessary to
151 specify the type of each field (i.e., is it an integer, a string, an
152 atom, or what?) This is done using one format character per field. If
153 there are more fields in the property than format characters supplied,
154 the last character will be repeated as many times as necessary for the
155 extra fields. The format characters and their meaning are as follows:
156 a The field holds an atom number. A field of this type should be
158 of size 32.
159 b The field is an boolean. A 0 means false while anything else
161 means true.
162 c The field is an unsigned number, a cardinal.
164 i The field is a signed integer.
166 m The field is a set of bit flags, 1 meaning on.
168 o The field is an array of icons, packed as a sequence of 32 bit
170 numbers consisting of the width, height and ARGB pixel values,
171 as defined for the _NET_WM_ICON property in the Extended Window
172 Manager Hints specification. A field of this type must be of
173 size 32.
174 s This field and the next ones until either a 0 or the end of the
176 property represent a sequence of bytes. This format character
177 is only usable with a field size of 8 and is most often used to
178 represent a string.
179 t This field and the next ones until either a 0 or the end of the
181 property represent an internationalized text string. This format
182 character is only usable with a field size of 8. The string is
183 assumed to be in an ICCCM compliant encoding and is converted to
184 the current locale encoding before being output.
185 u This field and the next ones until either a 0 or the end of the
187 property represent an UTF-8 encoded unicode string. This format
188 character is only usable with a field size of 8. If the string
189 is found to be an invalid character, the type of encoding viola‐
190 tion is printed instead, followed by the string formatted using
191 's'. When in an environment not capable of displaying UTF-8
192 encoded string, behaviour is identical to 's'.
193 x The field is a hex number (like 'c' but displayed in hex - most
195 useful for displaying window ids and the like)
196 An example format is 32ica which is the format for a property of three
198 fields of 32 bits each, the first holding a signed integer, the second
199 an unsigned integer, and the third an atom.
200 The format of a dformat unlike that of a format is not so rigid. The
202 only limitations on a dformat is that one may not start with a letter
203 or a dash. This is so that it can be distinguished from a property
204 name or an argument. A dformat is a text string containing special
205 characters instructing that various fields be printed at various points
206 in a manner similar to the formatting string used by printf. For exam‐
207 ple, the dformat " is ( $0, $1 \)\n" would render the POINT 3, -4 which
208 has a format of 32ii as " is ( 3, -4 )\n".
209 Any character other than a $, ?, \, or a ( in a dformat prints as
211 itself. To print out one of $, ?, \, or ( precede it by a \. For
212 example, to print out a $, use \$. Several special backslash sequences
213 are provided as shortcuts. \n will cause a newline to be displayed
214 while \t will cause a tab to be displayed. \o where o is an octal num‐
215 ber will display character number o.
216 A $ followed by a number n causes field number n to be displayed. The
218 format of the displayed field depends on the formatting character used
219 to describe it in the corresponding format. I.e., if a cardinal is
220 described by 'c' it will print in decimal while if it is described by a
221 'x' it is displayed in hex.
222 If the field is not present in the property (this is possible with some
224 properties), <field not available> is displayed instead. $n+ will dis‐
225 play field number n then a comma then field number n+1 then another
226 comma then ... until the last field defined. If field n is not
227 defined, nothing is displayed. This is useful for a property that is a
228 list of values.
229 A ? is used to start a conditional expression, a kind of if-then state‐
231 ment. ?exp(text) will display text if and only if exp evaluates to
232 non-zero. This is useful for two things. First, it allows fields to
233 be displayed if and only if a flag is set. And second, it allows a
234 value such as a state number to be displayed as a name rather than as
235 just a number. The syntax of exp is as follows:
236 exp ::= term | term=exp | !exp
238 term ::= n | $n | mn
240 The ! operator is a logical ``not'', changing 0 to 1 and any non-zero
242 value to 0. = is an equality operator. Note that internally all
243 expressions are evaluated as 32 bit numbers so -1 is not equal to
244 65535. = returns 1 if the two values are equal and 0 if not. n repre‐
245 sents the constant value n while $n represents the value of field num‐
246 ber n. mn is 1 if flag number n in the first field having format char‐
247 acter 'm' in the corresponding format is 1, 0 otherwise.
248 Examples: ?m3(count: $3\n) displays field 3 with a label of count if
250 and only if flag number 3 (count starts at 0!) is on.
251 ?$2=0(True)?!$2=0(False) displays the inverted value of field 2 as a
252 boolean.
253 In order to display a property, xprop needs both a format and a dfor‐
255 mat. Before xprop uses its default values of a format of 32x and a
256 dformat of " = { $0+ }\n", it searches several places in an attempt to
257 find more specific formats. First, a search is made using the name of
258 the property. If this fails, a search is made using the type of the
259 property. This allows type STRING to be defined with one set of for‐
260 mats while allowing property WM_NAME which is of type STRING to be
261 defined with a different format. In this way, the display formats for
262 a given type can be overridden for specific properties.
263 The locations searched are in order: the format if any specified with
265 the property name (as in 8x WM_NAME), the formats defined by -f options
266 in last to first order, the contents of the file specified by the -fs
267 option if any, the contents of the file specified by the environmental
268 variable XPROPFORMATS if any, and finally xprop's built in file of for‐
269 mats.
270 The format of the files referred to by the -fs argument and the XPROP‐
272 FORMATS variable is one or more lines of the following form:
273 name format [dformat]
275 Where name is either the name of a property or the name of a type, for‐
277 mat is the format to be used with name and dformat is the dformat to be
278 used with name. If dformat is not present, " = $0+\n" is assumed.
279
281 To display the name of the root window: xprop -root WM_NAME
282 To display the window manager hints for the clock: xprop -name xclock
284 WM_HINTS
285 To display the start of the cut buffer: xprop -root -len 100 CUT_BUF‐
287 FER0
288 To display the point size of the fixed font: xprop -font fixed
290 POINT_SIZE
291 To display all the properties of window # 0x200007: xprop -id 0x200007
293 To set a simple string property: xprop -root -format MY_ATOM_NAME 8s
295 -set MY_ATOM_NAME "my_value"
296
298 DISPLAY To get default display.
299 XPROPFORMATS
301 Specifies the name of a file from which additional formats are
302 to be obtained.
303
305 X(7), xdpyinfo(1), xwininfo(1), xdriinfo(1), glxinfo(1), xvinfo(1)
306
308 Mark Lillibridge, MIT Project Athena
309X Version 11 xprop 1.2.2 XPROP(1)