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
21 In the first synopsis form, the getconf utility shall write to the
22 standard output the value of the variable specified by the system_var
23 operand.
24 In the second synopsis form, the getconf utility shall write to the
26 standard output the value of the variable specified by the path_var op‐
27 erand for the path specified by the pathname operand.
28 The value of each configuration variable shall be determined as if it
30 were obtained by calling the function from which it is defined to be
31 available by this volume of IEEE Std 1003.1-2001 or by the System
32 Interfaces volume of IEEE Std 1003.1-2001 (see the OPERANDS section).
33 The value shall reflect conditions in the current operating environ‐
34 ment.
35
37 The getconf utility shall conform to the Base Definitions volume of
38 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
39 The following option shall be supported:
41 -v specification
43 Indicate a specific specification and version for which configu‐
45 ration variables shall be determined. If this option is not
46 specified, the values returned correspond to an implementation
47 default conforming compilation environment.
48 If the command:
50 getconf _POSIX_V6_ILP32_OFF32
53 does not write "-1\n" or "undefined\n" to standard output, then com‐
55 mands of the form:
56 getconf -v POSIX_V6_ILP32_OFF32 ...
59 determine values for configuration variables corresponding to the
61 POSIX_V6_ILP32_OFF32 compilation environment specified in c99, the
62 EXTENDED DESCRIPTION.
63 If the command:
65 getconf _POSIX_V6_ILP32_OFFBIG
68 does not write "-1\n" or "undefined\n" to standard output, then com‐
70 mands of the form:
71 getconf -v POSIX_V6_ILP32_OFFBIG ...
74 determine values for configuration variables corresponding to the
76 POSIX_V6_ILP32_OFFBIG compilation environment specified in c99, the
77 EXTENDED DESCRIPTION.
78 If the command:
80 getconf _POSIX_V6_LP64_OFF64
83 does not write "-1\n" or "undefined\n" to standard output, then com‐
85 mands of the form:
86 getconf -v POSIX_V6_LP64_OFF64 ...
89 determine values for configuration variables corresponding to the
91 POSIX_V6_LP64_OFF64 compilation environment specified in c99, the
92 EXTENDED DESCRIPTION.
93 If the command:
95 getconf _POSIX_V6_LPBIG_OFFBIG
98 does not write "-1\n" or "undefined\n" to standard output, then com‐
100 mands of the form:
101 getconf -v POSIX_V6_LPBIG_OFFBIG ...
104 determine values for configuration variables corresponding to the
106 POSIX_V6_LPBIG_OFFBIG compilation environment specified in c99, the
107 EXTENDED DESCRIPTION.
108
111 The following operands shall be supported:
112 path_var
114 A name of a configuration variable. All of the variables in the
115 Variable column of the table in the DESCRIPTION of the fpath‐
116 conf() function defined in the System Interfaces volume of
117 IEEE Std 1003.1-2001, without the enclosing braces, shall be
118 supported. The implementation may add other local variables.
119 pathname
121 A pathname for which the variable specified by path_var is to be
122 determined.
123 system_var
125 A name of a configuration variable. All of the following vari‐
126 ables shall be supported:
127 * The names in the Variable column of the table in the DESCRIP‐
129 TION of the sysconf() function in the System Interfaces vol‐
130 ume of IEEE Std 1003.1-2001, except for the entries corre‐
131 sponding to _SC_CLK_TCK, _SC_GETGR_R_SIZE_MAX, and
132 _SC_GETPW_R_SIZE_MAX, without the enclosing braces.
133 For compatibility with earlier versions, the following variable
135 names shall also be supported:
136 POSIX2_C_BIND
139 POSIX2_C_DEV
140 POSIX2_CHAR_TERM
141 POSIX2_FORT_DEV
142 POSIX2_FORT_RUN
143 POSIX2_LOCALEDEF
144 POSIX2_SW_DEV
145 POSIX2_UPE
146 POSIX2_VERSION
147 and shall be equivalent to the same name prefixed with an under‐
149 score. This requirement may be removed in a future version.
150 * The names of the symbolic constants used as the name argument
152 of the confstr() function in the System Interfaces volume of
153 IEEE Std 1003.1-2001, without the _CS_ prefix.
154 * The names of the symbolic constants listed under the headings
156 ``Maximum Values'' and ``Minimum Values'' in the description
157 of the <limits.h> header in the Base Definitions volume of
158 IEEE Std 1003.1-2001, without the enclosing braces.
159 For compatibility with earlier versions, the following variable
161 names shall also be supported:
162 POSIX2_BC_BASE_MAX
165 POSIX2_BC_DIM_MAX
166 POSIX2_BC_SCALE_MAX
167 POSIX2_BC_STRING_MAX
168 POSIX2_COLL_WEIGHTS_MAX
169 POSIX2_EXPR_NEST_MAX
170 POSIX2_LINE_MAX
171 POSIX2_RE_DUP_MAX
172 and shall be equivalent to the same name prefixed with an under‐
174 score. This requirement may be removed in a future version.
175 The implementation may add other local values.
177
180 Not used.
181
183 None.
184
186 The following environment variables shall affect the execution of get‐
187 conf:
188 LANG Provide a default value for the internationalization variables
190 that are unset or null. (See the Base Definitions volume of
191 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
192 ables for the precedence of internationalization variables used
193 to determine the values of locale categories.)
194 LC_ALL If set to a non-empty string value, override the values of all
196 the other internationalization variables.
197 LC_CTYPE
199 Determine the locale for the interpretation of sequences of
200 bytes of text data as characters (for example, single-byte as
201 opposed to multi-byte characters in arguments).
202 LC_MESSAGES
204 Determine the locale that should be used to affect the format
205 and contents of diagnostic messages written to standard error.
206 NLSPATH
208 Determine the location of message catalogs for the processing of
209 LC_MESSAGES .
210
213 Default.
214
216 If the specified variable is defined on the system and its value is
217 described to be available from the confstr() function defined in the
218 System Interfaces volume of IEEE Std 1003.1-2001, its value shall be
219 written in the following format:
220 "%s\n", <value>
223 Otherwise, if the specified variable is defined on the system, its
225 value shall be written in the following format:
226 "%d\n", <value>
229 If the specified variable is valid, but is undefined on the system,
231 getconf shall write using the following format:
232 "undefined\n"
235 If the variable name is invalid or an error occurs, nothing shall be
237 written to standard output.
238
240 The standard error shall be used only for diagnostic messages.
241
243 None.
244
246 None.
247
249 The following exit values shall be returned:
250 0 The specified variable is valid and information about its cur‐
252 rent state was written successfully.
253 >0 An error occurred.
255
258 Default.
259 The following sections are informative.
261
263 None.
264
266 The following example illustrates the value of {NGROUPS_MAX}:
267 getconf NGROUPS_MAX
270 The following example illustrates the value of {NAME_MAX} for a spe‐
272 cific directory:
273 getconf NAME_MAX /usr
276 The following example shows how to deal more carefully with results
278 that might be unspecified:
279 if value=$(getconf PATH_MAX /usr); then
282 if [ "$value" = "undefined" ]; then
283 echo PATH_MAX in /usr is infinite.
284 else
285 echo PATH_MAX in /usr is $value.
286 fi
287 else
288 echo Error in getconf.
289 fi
290 Note that:
292 sysconf(_SC_POSIX_C_BIND);
295 and:
297 system("getconf POSIX2_C_BIND");
300 in a C program could give different answers. The sysconf() call sup‐
302 plies a value that corresponds to the conditions when the program was
303 either compiled or executed, depending on the implementation; the sys‐
304 tem() call to getconf always supplies a value corresponding to condi‐
305 tions when the program is executed.
306
308 The original need for this utility, and for the confstr() function, was
309 to provide a way of finding the configuration-defined default value for
310 the PATH environment variable. Since PATH can be modified by the user
311 to include directories that could contain utilities replacing the stan‐
312 dard utilities, shell scripts need a way to determine the system-sup‐
313 plied PATH environment variable value that contains the correct search
314 path for the standard utilities. It was later suggested that access to
315 the other variables described in this volume of IEEE Std 1003.1-2001
316 could also be useful to applications.
317 This functionality of getconf would not be adequately subsumed by
319 another command such as:
320 grep var /etc/conf
323 because such a strategy would provide correct values for neither those
325 variables that can vary at runtime, nor those that can vary depending
326 on the path.
327 Early proposal versions of getconf specified exit status 1 when the
329 specified variable was valid, but not defined on the system. The output
330 string "undefined" is now used to specify this case with exit code 0
331 because so many things depend on an exit code of zero when an invoked
332 utility is successful.
333
335 None.
336
338 c99, the Base Definitions volume of IEEE Std 1003.1-2001, <limits.h>,
339 the System Interfaces volume of IEEE Std 1003.1-2001, confstr(), path‐
340 conf(), sysconf(), system()
341
343 Portions of this text are reprinted and reproduced in electronic form
344 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
345 -- Portable Operating System Interface (POSIX), The Open Group Base
346 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
347 Electrical and Electronics Engineers, Inc and The Open Group. In the
348 event of any discrepancy between this version and the original IEEE and
349 The Open Group Standard, the original IEEE and The Open Group Standard
350 is the referee document. The original Standard can be obtained online
351 at http://www.opengroup.org/unix/online.html .
352IEEE/The Open Group 2003 GETCONF(1P)