1GETCONF(P) POSIX Programmer's Manual GETCONF(P)
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6 getconf - get configuration values
7
9 getconf [ -v specification ] system_var
10 getconf [ -v specification ] path_var pathname
12
15 In the first synopsis form, the getconf utility shall write to the
16 standard output the value of the variable specified by the system_var
17 operand.
18 In the second synopsis form, the getconf utility shall write to the
20 standard output the value of the variable specified by the path_var op‐
21 erand for the path specified by the pathname operand.
22 The value of each configuration variable shall be determined as if it
24 were obtained by calling the function from which it is defined to be
25 available by this volume of IEEE Std 1003.1-2001 or by the System
26 Interfaces volume of IEEE Std 1003.1-2001 (see the OPERANDS section).
27 The value shall reflect conditions in the current operating environ‐
28 ment.
29
31 The getconf utility shall conform to the Base Definitions volume of
32 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
33 The following option shall be supported:
35 -v specification
37 Indicate a specific specification and version for which configu‐
39 ration variables shall be determined. If this option is not
40 specified, the values returned correspond to an implementation
41 default conforming compilation environment.
42 If the command:
44 getconf _POSIX_V6_ILP32_OFF32
47 does not write "-1\n" or "undefined\n" to standard output, then com‐
49 mands of the form:
50 getconf -v POSIX_V6_ILP32_OFF32 ...
53 determine values for configuration variables corresponding to the
55 POSIX_V6_ILP32_OFF32 compilation environment specified in c99 , the
56 EXTENDED DESCRIPTION.
57 If the command:
59 getconf _POSIX_V6_ILP32_OFFBIG
62 does not write "-1\n" or "undefined\n" to standard output, then com‐
64 mands of the form:
65 getconf -v POSIX_V6_ILP32_OFFBIG ...
68 determine values for configuration variables corresponding to the
70 POSIX_V6_ILP32_OFFBIG compilation environment specified in c99 , the
71 EXTENDED DESCRIPTION.
72 If the command:
74 getconf _POSIX_V6_LP64_OFF64
77 does not write "-1\n" or "undefined\n" to standard output, then com‐
79 mands of the form:
80 getconf -v POSIX_V6_LP64_OFF64 ...
83 determine values for configuration variables corresponding to the
85 POSIX_V6_LP64_OFF64 compilation environment specified in c99 , the
86 EXTENDED DESCRIPTION.
87 If the command:
89 getconf _POSIX_V6_LPBIG_OFFBIG
92 does not write "-1\n" or "undefined\n" to standard output, then com‐
94 mands of the form:
95 getconf -v POSIX_V6_LPBIG_OFFBIG ...
98 determine values for configuration variables corresponding to the
100 POSIX_V6_LPBIG_OFFBIG compilation environment specified in c99 , the
101 EXTENDED DESCRIPTION.
102
105 The following operands shall be supported:
106 path_var
108 A name of a configuration variable. All of the variables in the
109 Variable column of the table in the DESCRIPTION of the fpath‐
110 conf() function defined in the System Interfaces volume of
111 IEEE Std 1003.1-2001, without the enclosing braces, shall be
112 supported. The implementation may add other local variables.
113 pathname
115 A pathname for which the variable specified by path_var is to be
116 determined.
117 system_var
119 A name of a configuration variable. All of the following vari‐
120 ables shall be supported:
121 * The names in the Variable column of the table in the DESCRIP‐
123 TION of the sysconf() function in the System Interfaces vol‐
124 ume of IEEE Std 1003.1-2001, except for the entries corre‐
125 sponding 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 variable
129 names shall also be supported:
130 POSIX2_C_BIND
133 POSIX2_C_DEV
134 POSIX2_CHAR_TERM
135 POSIX2_FORT_DEV
136 POSIX2_FORT_RUN
137 POSIX2_LOCALEDEF
138 POSIX2_SW_DEV
139 POSIX2_UPE
140 POSIX2_VERSION
141 and shall be equivalent to the same name prefixed with an under‐
143 score. This requirement may be removed in a future version.
144 * The names of the symbolic constants used as the name argument
146 of the confstr() function in the System Interfaces volume of
147 IEEE Std 1003.1-2001, without the _CS_ prefix.
148 * The names of the symbolic constants listed under the headings
150 ``Maximum Values'' and ``Minimum Values'' in the description
151 of the <limits.h> header in the Base Definitions volume of
152 IEEE Std 1003.1-2001, without the enclosing braces.
153 For compatibility with earlier versions, the following variable
155 names shall also be supported:
156 POSIX2_BC_BASE_MAX
159 POSIX2_BC_DIM_MAX
160 POSIX2_BC_SCALE_MAX
161 POSIX2_BC_STRING_MAX
162 POSIX2_COLL_WEIGHTS_MAX
163 POSIX2_EXPR_NEST_MAX
164 POSIX2_LINE_MAX
165 POSIX2_RE_DUP_MAX
166 and shall be equivalent to the same name prefixed with an under‐
168 score. This requirement may be removed in a future version.
169 The implementation may add other local values.
171
174 Not used.
175
177 None.
178
180 The following environment variables shall affect the execution of get‐
181 conf:
182 LANG Provide a default value for the internationalization variables
184 that are unset or null. (See the Base Definitions volume of
185 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
186 ables for the precedence of internationalization variables used
187 to determine the values of locale categories.)
188 LC_ALL If set to a non-empty string value, override the values of all
190 the other internationalization variables.
191 LC_CTYPE
193 Determine the locale for the interpretation of sequences of
194 bytes of text data as characters (for example, single-byte as
195 opposed to multi-byte characters in arguments).
196 LC_MESSAGES
198 Determine the locale that should be used to affect the format
199 and contents of diagnostic messages written to standard error.
200 NLSPATH
202 Determine the location of message catalogs for the processing of
203 LC_MESSAGES .
204
207 Default.
208
210 If the specified variable is defined on the system and its value is
211 described to be available from the confstr() function defined in the
212 System Interfaces volume of IEEE Std 1003.1-2001, its value shall be
213 written in the following format:
214 "%s\n", <value>
217 Otherwise, if the specified variable is defined on the system, its
219 value shall be written in the following format:
220 "%d\n", <value>
223 If the specified variable is valid, but is undefined on the system,
225 getconf shall write using the following format:
226 "undefined\n"
229 If the variable name is invalid or an error occurs, nothing shall be
231 written to standard output.
232
234 The standard error shall be used only for diagnostic messages.
235
237 None.
238
240 None.
241
243 The following exit values shall be returned:
244 0 The specified variable is valid and information about its cur‐
246 rent state was written successfully.
247 >0 An error occurred.
249
252 Default.
253 The following sections are informative.
255
257 None.
258
260 The following example illustrates the value of {NGROUPS_MAX}:
261 getconf NGROUPS_MAX
264 The following example illustrates the value of {NAME_MAX} for a spe‐
266 cific directory:
267 getconf NAME_MAX /usr
270 The following example shows how to deal more carefully with results
272 that might be unspecified:
273 if value=$(getconf PATH_MAX /usr); then
276 if [ "$value" = "undefined" ]; then
277 echo PATH_MAX in /usr is infinite.
278 else
279 echo PATH_MAX in /usr is $value.
280 fi
281 else
282 echo Error in getconf.
283 fi
284 Note that:
286 sysconf(_SC_POSIX_C_BIND);
289 and:
291 system("getconf POSIX2_C_BIND");
294 in a C program could give different answers. The sysconf() call sup‐
296 plies a value that corresponds to the conditions when the program was
297 either compiled or executed, depending on the implementation; the sys‐
298 tem() call to getconf always supplies a value corresponding to condi‐
299 tions when the program is executed.
300
302 The original need for this utility, and for the confstr() function, was
303 to provide a way of finding the configuration-defined default value for
304 the PATH environment variable. Since PATH can be modified by the user
305 to include directories that could contain utilities replacing the stan‐
306 dard utilities, shell scripts need a way to determine the system-sup‐
307 plied PATH environment variable value that contains the correct search
308 path for the standard utilities. It was later suggested that access to
309 the other variables described in this volume of IEEE Std 1003.1-2001
310 could also be useful to applications.
311 This functionality of getconf would not be adequately subsumed by
313 another command such as:
314 grep var /etc/conf
317 because such a strategy would provide correct values for neither those
319 variables that can vary at runtime, nor those that can vary depending
320 on the path.
321 Early proposal versions of getconf specified exit status 1 when the
323 specified variable was valid, but not defined on the system. The output
324 string "undefined" is now used to specify this case with exit code 0
325 because so many things depend on an exit code of zero when an invoked
326 utility is successful.
327
329 None.
330
332 c99 , the Base Definitions volume of IEEE Std 1003.1-2001, <limits.h>,
333 the System Interfaces volume of IEEE Std 1003.1-2001, confstr(), path‐
334 conf(), sysconf(), system()
335
337 Portions of this text are reprinted and reproduced in electronic form
338 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
339 -- Portable Operating System Interface (POSIX), The Open Group Base
340 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
341 Electrical and Electronics Engineers, Inc and The Open Group. In the
342 event of any discrepancy between this version and the original IEEE and
343 The Open Group Standard, the original IEEE and The Open Group Standard
344 is the referee document. The original Standard can be obtained online
345 at http://www.opengroup.org/unix/online.html .
346IEEE/The Open Group 2003 GETCONF(P)