1GETCONF(1P) POSIX Programmer's Manual GETCONF(1P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 getconf — get configuration values
13
15 getconf [-v specification] system_var
16 getconf [-v specification] path_var pathname
18
20 In the first synopsis form, the getconf utility shall write to the
21 standard output the value of the variable specified by the system_var
22 operand.
23 In the second synopsis form, the getconf utility shall write to the
25 standard output the value of the variable specified by the path_var op‐
26 erand for the path specified by the pathname operand.
27 The value of each configuration variable shall be determined as if it
29 were obtained by calling the function from which it is defined to be
30 available by this volume of POSIX.1‐2017 or by the System Interfaces
31 volume of POSIX.1‐2017 (see the OPERANDS section). The value shall
32 reflect conditions in the current operating environment.
33
35 The getconf utility shall conform to the Base Definitions volume of
36 POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines.
37 The following option shall be supported:
39 -v specification
41 Indicate a specific specification and version for which con‐
42 figuration variables shall be determined. If this option is
43 not specified, the values returned correspond to an implemen‐
44 tation default conforming compilation environment.
45 If the command:
47 getconf _POSIX_V7_ILP32_OFF32
50 does not write "-1\n" or "undefined\n" to standard output,
52 then commands of the form:
53 getconf -v POSIX_V7_ILP32_OFF32 ...
56 determine values for configuration variables corresponding to
58 the POSIX_V7_ILP32_OFF32 compilation environment specified in
59 c99, the EXTENDED DESCRIPTION.
60 If the command:
62 getconf _POSIX_V7_ILP32_OFFBIG
65 does not write "-1\n" or "undefined\n" to standard output,
67 then commands of the form:
68 getconf -v POSIX_V7_ILP32_OFFBIG ...
71 determine values for configuration variables corresponding to
73 the POSIX_V7_ILP32_OFFBIG compilation environment specified
74 in c99, the EXTENDED DESCRIPTION.
75 If the command:
77 getconf _POSIX_V7_LP64_OFF64
80 does not write "-1\n" or "undefined\n" to standard output,
82 then commands of the form:
83 getconf -v POSIX_V7_LP64_OFF64 ...
86 determine values for configuration variables corresponding to
88 the POSIX_V7_LP64_OFF64 compilation environment specified in
89 c99, the EXTENDED DESCRIPTION.
90 If the command:
92 getconf _POSIX_V7_LPBIG_OFFBIG
95 does not write "-1\n" or "undefined\n" to standard output,
97 then commands of the form:
98 getconf -v POSIX_V7_LPBIG_OFFBIG ...
101 determine values for configuration variables corresponding to
103 the POSIX_V7_LPBIG_OFFBIG compilation environment specified
104 in c99, the EXTENDED DESCRIPTION.
105
107 The following operands shall be supported:
108 path_var A name of a configuration variable. All of the variables in
110 the Variable column of the table in the DESCRIPTION of the
111 fpathconf() function defined in the System Interfaces volume
112 of POSIX.1‐2017, without the enclosing braces, shall be sup‐
113 ported. The implementation may add other local variables.
114 pathname A pathname for which the variable specified by path_var is to
116 be determined.
117 system_var
119 A name of a configuration variable. All of the following
120 variables shall be supported:
121 * The names in the Variable column of the table in the
123 DESCRIPTION of the sysconf() function in the System
124 Interfaces volume of POSIX.1‐2017, except for the entries
125 corresponding to _SC_CLK_TCK, _SC_GETGR_R_SIZE_MAX, and
126 _SC_GETPW_R_SIZE_MAX, without the enclosing braces.
127 For compatibility with earlier versions, the following
129 variable names shall also be supported: POSIX2_C_BIND
130 POSIX2_C_DEV POSIX2_CHAR_TERM POSIX2_FORT_DEV
131 POSIX2_FORT_RUN POSIX2_LOCALEDEF POSIX2_SW_DEV POSIX2_UPE
132 POSIX2_VERSION
133 and shall be equivalent to the same name prefixed with an
135 <underscore>. This requirement may be removed in a
136 future version.
137 * The names of the symbolic constants used as the name
139 argument of the confstr() function in the System Inter‐
140 faces volume of POSIX.1‐2017, without the _CS_ prefix.
141 * The names of the symbolic constants listed under the
143 headings ``Maximum Values'' and ``Minimum Values'' in the
144 description of the <limits.h> header in the Base Defini‐
145 tions volume of POSIX.1‐2017, without the enclosing
146 braces.
147 For compatibility with earlier versions, the following
149 variable names shall also be supported:
150 POSIX2_BC_BASE_MAX POSIX2_BC_DIM_MAX POSIX2_BC_SCALE_MAX
151 POSIX2_BC_STRING_MAX POSIX2_COLL_WEIGHTS_MAX
152 POSIX2_EXPR_NEST_MAX POSIX2_LINE_MAX POSIX2_RE_DUP_MAX
153 and shall be equivalent to the same name prefixed with an
155 <underscore>. This requirement may be removed in a
156 future version.
157 The implementation may add other local values.
159
161 Not used.
162
164 None.
165
167 The following environment variables shall affect the execution of get‐
168 conf:
169 LANG Provide a default value for the internationalization vari‐
171 ables that are unset or null. (See the Base Definitions vol‐
172 ume of POSIX.1‐2017, Section 8.2, Internationalization Vari‐
173 ables for the precedence of internationalization variables
174 used to determine the values of locale categories.)
175 LC_ALL If set to a non-empty string value, override the values of
177 all the other internationalization variables.
178 LC_CTYPE Determine the locale for the interpretation of sequences of
180 bytes of text data as characters (for example, single-byte as
181 opposed to multi-byte characters in arguments).
182 LC_MESSAGES
184 Determine the locale that should be used to affect the format
185 and contents of diagnostic messages written to standard
186 error.
187 NLSPATH Determine the location of message catalogs for the processing
189 of LC_MESSAGES.
190
192 Default.
193
195 If the specified variable is defined on the system and its value is
196 described to be available from the confstr() function defined in the
197 System Interfaces volume of POSIX.1‐2017, its value shall be written in
198 the following format:
199 "%s\n", <value>
202 Otherwise, if the specified variable is defined on the system, its
204 value shall be written in the following format:
205 "%d\n", <value>
208 If the specified variable is valid, but is undefined on the system,
210 getconf shall write using the following format:
211 "undefined\n"
214 If the variable name is invalid or an error occurs, nothing shall be
216 written to standard output.
217
219 The standard error shall be used only for diagnostic messages.
220
222 None.
223
225 None.
226
228 The following exit values shall be returned:
229 0 The specified variable is valid and information about its current
231 state was written successfully.
232 >0 An error occurred.
234
236 Default.
237 The following sections are informative.
239
241 None.
242
244 The following example illustrates the value of {NGROUPS_MAX}:
245 getconf NGROUPS_MAX
248 The following example illustrates the value of {NAME_MAX} for a spe‐
250 cific directory:
251 getconf NAME_MAX /usr
254 The following example shows how to deal more carefully with results
256 that might be unspecified:
257 if value=$(getconf PATH_MAX /usr); then
260 if [ "$value" = "undefined" ]; then
261 echo PATH_MAX in /usr is indeterminate.
262 else
263 echo PATH_MAX in /usr is $value.
264 fi
265 else
266 echo Error in getconf.
267 fi
268
270 The original need for this utility, and for the confstr() function, was
271 to provide a way of finding the configuration-defined default value for
272 the PATH environment variable. Since PATH can be modified by the user
273 to include directories that could contain utilities replacing the stan‐
274 dard utilities, shell scripts need a way to determine the system-sup‐
275 plied PATH environment variable value that contains the correct search
276 path for the standard utilities. It was later suggested that access to
277 the other variables described in this volume of POSIX.1‐2017 could also
278 be useful to applications.
279 This functionality of getconf would not be adequately subsumed by
281 another command such as:
282 grep var /etc/conf
285 because such a strategy would provide correct values for neither those
287 variables that can vary at runtime, nor those that can vary depending
288 on the path.
289 Early proposal versions of getconf specified exit status 1 when the
291 specified variable was valid, but not defined on the system. The output
292 string "undefined" is now used to specify this case with exit code 0
293 because so many things depend on an exit code of zero when an invoked
294 utility is successful.
295
297 None.
298
300 c99
301 The Base Definitions volume of POSIX.1‐2017, Chapter 8, Environment
303 Variables, Section 12.2, Utility Syntax Guidelines, <limits.h>
304 The System Interfaces volume of POSIX.1‐2017, confstr(), fpathconf(),
306 sysconf(), system()
307
309 Portions of this text are reprinted and reproduced in electronic form
310 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
311 table Operating System Interface (POSIX), The Open Group Base Specifi‐
312 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
313 Electrical and Electronics Engineers, Inc and The Open Group. In the
314 event of any discrepancy between this version and the original IEEE and
315 The Open Group Standard, the original IEEE and The Open Group Standard
316 is the referee document. The original Standard can be obtained online
317 at http://www.opengroup.org/unix/online.html .
318 Any typographical or formatting errors that appear in this page are
320 most likely to have been introduced during the conversion of the source
321 files to man page format. To report such errors, see https://www.ker‐
322 nel.org/doc/man-pages/reporting_bugs.html .
323IEEE/The Open Group 2017 GETCONF(1P)