1AR(P) POSIX Programmer's Manual AR(P)
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6 ar - create and maintain library archives
7
9 ar -d[-v] archive file ...
10 ar -m [-v] archive file ...
14 ar -m -a[-v] posname archive file ...
16 ar -m -b[-v] posname archive file ...
18 ar -m -i[-v] posname archive file ...
20 ar -p[-v][-s]archive [file ...]
22 ar -q[-cv] archive file ...
26 ar -r[-cuv] archive file ...
28 ar -r -a[-cuv] posname archive file ...
32 ar -r -b[-cuv] posname archive file ...
34 ar -r -i[-cuv] posname archive file ...
36 ar -t[-v][-s]archive [file ...]
38 ar -x[-v][-sCT]archive [file ...]
40
43 The ar utility is part of the Software Development Utilities option.
44 The ar utility can be used to create and maintain groups of files com‐
46 bined into an archive. Once an archive has been created, new files can
47 be added, and existing files in an archive can be extracted, deleted,
48 or replaced. When an archive consists entirely of valid object files,
49 the implementation shall format the archive so that it is usable as a
50 library for link editing (see c99 and fort77). When some of the
51 archived files are not valid object files, the suitability of the ar‐
52 chive for library use is undefined. If an archive consists entirely
53 of printable files, the entire archive shall be printable.
54 When ar creates an archive, it creates administrative information indi‐
56 cating whether a symbol table is present in the archive. When there is
57 at least one object file that ar recognizes as such in the archive, an
58 archive symbol table shall be created in the archive and maintained by
59 ar; it is used by the link editor to search the archive. Whenever the
60 ar utility is used to create or update the contents of such an archive,
61 the symbol table shall be rebuilt. The -s option shall force the symbol
62 table to be rebuilt.
63 All file operands can be pathnames. However, files within archives
65 shall be named by a filename, which is the last component of the path‐
66 name used when the file was entered into the archive. The comparison of
67 file operands to the names of files in archives shall be performed by
68 comparing the last component of the operand to the name of the file in
69 the archive.
70 It is unspecified whether multiple files in the archive may be identi‐
72 cally named. In the case of such files, however, each file and pos‐
73 name operand shall match only the first file in the archive having a
74 name that is the same as the last component of the operand.
75
77 The ar utility shall conform to the Base Definitions volume of
78 IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
79 The following options shall be supported:
81 -a Position new files in the archive after the file named by the
83 posname operand.
84 -b Position new files in the archive before the file named by the
86 posname operand.
87 -c Suppress the diagnostic message that is written to standard
89 error by default when the archive archive is created.
90 -C Prevent extracted files from replacing like-named files in the
92 file system. This option is useful when -T is also used, to pre‐
93 vent truncated filenames from replacing files with the same pre‐
94 fix.
95 -d Delete one or more files from archive.
97 -i Position new files in the archive before the file in the archive
99 named by the posname operand (equivalent to -b).
100 -m Move the named files in the archive. The -a, -b, or -i options
102 with the posname operand indicate the position; otherwise, move
103 the names files in the archive to the end of the archive.
104 -p Write the contents of the files in the archive named by file op‐
106 erands from archive to the standard output. If no file operands
107 are specified, the contents of all files in the archive shall be
108 written in the order of the archive.
109 -q Append the named files to the end of the archive. In this case
111 ar does not check whether the added files are already in the ar‐
112 chive. This is useful to bypass the searching otherwise done
113 when creating a large archive piece by piece.
114 -r Replace or add files to archive. If the archive named by archive
116 does not exist, a new archive shall be created and a diagnostic
117 message shall be written to standard error (unless the -c option
118 is specified). If no files are specified and the archive exists,
119 the results are undefined. Files that replace existing files in
120 the archive shall not change the order of the archive. Files
121 that do not replace existing files in the archive shall be
122 appended to the archive unless a -a, -b, or -i option speci‐
123 fies another position.
124 -s Force the regeneration of the archive symbol table even if ar is
126 not invoked with an option that modifies the archive contents.
127 This option is useful to restore the archive symbol table after
128 it has been stripped; see strip.
129 -t Write a table of contents of archive to the standard output.
131 The files specified by the file operands shall be included in
132 the written list. If no file operands are specified, all files
133 in archive shall be included in the order of the archive.
134 -T Allow filename truncation of extracted files whose archive names
136 are longer than the file system can support. By default,
137 extracting a file with a name that is too long shall be an
138 error; a diagnostic message shall be written and the file shall
139 not be extracted.
140 -u Update older files in the archive. When used with the -r option,
142 files in the archive shall be replaced only if the corresponding
143 file has a modification time that is at least as new as the mod‐
144 ification time of the file in the archive.
145 -v Give verbose output. When used with the option characters -d,
147 -r, or -x, write a detailed file-by-file description of the ar‐
148 chive creation and maintenance activity, as described in the
149 STDOUT section.
150 When used with -p, write the name of the file in the archive to the
152 standard output before writing the file in the archive itself to the
153 standard output, as described in the STDOUT section.
154 When used with -t, include a long listing of information about the
156 files in the archive, as described in the STDOUT section.
157 -x Extract the files in the archive named by the file operands from
159 archive. The contents of the archive shall not be changed. If no
160 file operands are given, all files in the archive shall be
161 extracted. The modification time of each file extracted shall be
162 set to the time the file is extracted from the archive.
163
166 The following operands shall be supported:
167 archive
169 A pathname of the archive.
170 file A pathname. Only the last component shall be used when comparing
172 against the names of files in the archive. If two or more file
173 operands have the same last pathname component (basename), the
174 results are unspecified. The implementation's archive format
175 shall not truncate valid filenames of files added to or replaced
176 in the archive.
177 posname
179 The name of a file in the archive, used for relative position‐
180 ing; see options -m and -r.
181
184 Not used.
185
187 The archive named by archive shall be a file in the format created by
188 ar -r.
189
191 The following environment variables shall affect the execution of ar:
192 LANG Provide a default value for the internationalization variables
194 that are unset or null. (See the Base Definitions volume of
195 IEEE Std 1003.1-2001, Section 8.2, Internationalization Vari‐
196 ables for the precedence of internationalization variables used
197 to determine the values of locale categories.)
198 LC_ALL If set to a non-empty string value, override the values of all
200 the other internationalization variables.
201 LC_CTYPE
203 Determine the locale for the interpretation of sequences of
204 bytes of text data as characters (for example, single-byte as
205 opposed to multi-byte characters in arguments and input files).
206 LC_MESSAGES
208 Determine the locale that should be used to affect the format
209 and contents of diagnostic messages written to standard error.
210 LC_TIME
212 Determine the format and content for date and time strings writ‐
213 ten by ar -tv.
214 NLSPATH
216 Determine the location of message catalogs for the processing of
217 LC_MESSAGES .
218 TMPDIR Determine the pathname that overrides the default directory for
220 temporary files, if any.
221 TZ Determine the timezone used to calculate date and time strings
223 written by ar -tv. If TZ is unset or null, an unspecified
224 default timezone shall be used.
225
228 Default.
229
231 If the -d option is used with the -v option, the standard output format
232 shall be:
233 "d - %s\n", <file>
236 where file is the operand specified on the command line.
238 If the -p option is used with the -v option, ar shall precede the con‐
240 tents of each file with:
241 "\n<%s>\n\n", <file>
244 where file is the operand specified on the command line, if file oper‐
246 ands were specified, and the name of the file in the archive if they
247 were not.
248 If the -r option is used with the -v option:
250 * If file is already in the archive, the standard output format shall
252 be:
253 "r - %s\n", <file>
256 where <file> is the operand specified on the command line.
258 * If file is not already in the archive, the standard output format
260 shall be:
261 "a - %s\n", <file>
264 where <file> is the operand specified on the command line.
266 If the -t option is used, ar shall write the names of the files in the
268 archive to the standard output in the format:
269 "%s\n", <file>
272 where file is the operand specified on the command line, if file oper‐
274 ands were specified, or the name of the file in the archive if they
275 were not.
276 If the -t option is used with the -v option, the standard output format
278 shall be:
279 "%s %u/%u %u %s %d %d:%d %d %s\n", <member mode>, <user ID>,
282 <group ID>, <number of bytes in member>,
283 <abbreviated month>, <day-of-month>, <hour>,
284 <minute>, <year>, <file>
285 where:
287 <file> Shall be the operand specified on the command line, if file op‐
289 erands were specified, or the name of the file in the archive if
290 they were not.
291 <member mode>
293 Shall be formatted the same as the <file mode> string defined in
295 the STDOUT section of ls, except that the first character, the
296 <entry type>, is not used; the string represents the file mode
297 of the file in the archive at the time it was added to or
298 replaced in the archive.
299 The following represent the last-modification time of a file when it
302 was most recently added to or replaced in the archive:
303 <abbreviated month>
305 Equivalent to the format of the %b conversion specification for‐
307 mat in date.
308 <day-of-month>
310 Equivalent to the format of the %e conversion specification for‐
312 mat in date.
313 <hour> Equivalent to the format of the %H conversion specification for‐
315 mat in date.
316 <minute>
318 Equivalent to the format of the %M conversion specification for‐
319 mat in date.
320 <year> Equivalent to the format of the %Y conversion specification for‐
322 mat in date.
323 When LC_TIME does not specify the POSIX locale, a different format and
326 order of presentation of these fields relative to each other may be
327 used in a format appropriate in the specified locale.
328 If the -x option is used with the -v option, the standard output format
330 shall be:
331 "x - %s\n", <file>
334 where file is the operand specified on the command line, if file oper‐
336 ands were specified, or the name of the file in the archive if they
337 were not.
338
340 The standard error shall be used only for diagnostic messages. The
341 diagnostic message about creating a new archive when -c is not speci‐
342 fied shall not modify the exit status.
343
345 Archives are files with unspecified formats.
346
348 None.
349
351 The following exit values shall be returned:
352 0 Successful completion.
354 >0 An error occurred.
356
359 Default.
360 The following sections are informative.
362
364 None.
365
367 None.
368
370 The archive format is not described. It is recognized that there are
371 several known ar formats, which are not compatible. The ar utility is
372 included, however, to allow creation of archives that are intended for
373 use only on one machine. The archive is specified as a file, and it can
374 be moved as a file. This does allow an archive to be moved from one
375 machine to another machine that uses the same implementation of ar.
376 Utilities such as pax (and its forebears tar and cpio) also provide
378 portable "archives". This is a not a duplication; the ar utility is
379 included to provide an interface primarily for make and the compilers,
380 based on a historical model.
381 In historical implementations, the -q option (available on XSI-conform‐
383 ing systems) is known to execute quickly because ar does not check on
384 whether the added members are already in the archive. This is useful to
385 bypass the searching otherwise done when creating a large archive
386 piece-by-piece. These remarks may but need not remain true for a brand
387 new implementation of this utility; hence, these remarks have been
388 moved into the RATIONALE.
389 BSD implementations historically required applications to provide the
391 -s option whenever the archive was supposed to contain a symbol table.
392 As in this volume of IEEE Std 1003.1-2001, System V historically cre‐
393 ates or updates an archive symbol table whenever an object file is
394 removed from, added to, or updated in the archive.
395 The OPERANDS section requires what might seem to be true without speci‐
397 fying it: the archive cannot truncate the filenames below {NAME_MAX}.
398 Some historical implementations do so, however, causing unexpected
399 results for the application. Therefore, this volume of
400 IEEE Std 1003.1-2001 makes the requirement explicit to avoid misunder‐
401 standings.
402 According to the System V documentation, the options -dmpqrtx are not
404 required to begin with a hyphen ( '-' ). This volume of
405 IEEE Std 1003.1-2001 requires that a conforming application use the
406 leading hyphen.
407 The archive format used by the 4.4 BSD implementation is documented in
409 this RATIONALE as an example: A file created by ar begins with the
410 "magic" string "!<arch>\n" . The rest of the archive is made up of
411 objects, each of which is composed of a header for a file, a possible
412 filename, and the file contents. The header is portable between machine
413 architectures, and, if the file contents are printable, the archive is
414 itself printable.
415 The header is made up of six ASCII fields, followed by a two-character
417 trailer. The fields are the object name (16 characters), the file last
418 modification time (12 characters), the user and group IDs (each 6 char‐
419 acters), the file mode (8 characters), and the file size (10 charac‐
420 ters). All numeric fields are in decimal, except for the file mode,
421 which is in octal.
422 The modification time is the file st_mtime field. The user and group
424 IDs are the file st_uid and st_gid fields. The file mode is the file
425 st_mode field. The file size is the file st_size field. The two-byte
426 trailer is the string "`<newline>" .
427 Only the name field has any provision for overflow. If any filename is
429 more than 16 characters in length or contains an embedded space, the
430 string "#1/" followed by the ASCII length of the name is written in the
431 name field. The file size (stored in the archive header) is incremented
432 by the length of the name. The name is then written immediately follow‐
433 ing the archive header.
434 Any unused characters in any of these fields are written as <space>s.
436 If any fields are their particular maximum number of characters in
437 length, there is no separation between the fields.
438 Objects in the archive are always an even number of bytes long; files
440 that are an odd number of bytes long are padded with a <newline>,
441 although the size in the header does not reflect this.
442 The ar utility description requires that (when all its members are
444 valid object files) ar produce an object code library, which the link‐
445 age editor can use to extract object modules. If the linkage editor
446 needs a symbol table to permit random access to the archive, ar must
447 provide it; however, ar does not require a symbol table.
448 The BSD -o option was omitted. It is a rare conforming application that
450 uses ar to extract object code from a library with concern for its mod‐
451 ification time, since this can only be of importance to make. Hence,
452 since this functionality is not deemed important for applications
453 portability, the modification time of the extracted files is set to the
454 current time.
455 There is at least one known implementation (for a small computer) that
457 can accommodate only object files for that system, disallowing mixed
458 object and other files. The ability to handle any type of file is not
459 only historical practice for most implementations, but is also a rea‐
460 sonable expectation.
461 Consideration was given to changing the output format of ar -tv to the
463 same format as the output of ls -l. This would have made parsing the
464 output of ar the same as that of ls. This was rejected in part because
465 the current ar format is commonly used and changes would break histori‐
466 cal usage. Second, ar gives the user ID and group ID in numeric format
467 separated by a slash. Changing this to be the user name and group name
468 would not be correct if the archive were moved to a machine that con‐
469 tained a different user database. Since ar cannot know whether the ar‐
470 chive was generated on the same machine, it cannot tell what to report.
471 The text on the -ur option combination is historical practice-since one
473 filename can easily represent two different files (for example, /a/foo
474 and /b/foo), it is reasonable to replace the file in the archive even
475 when the modification time in the archive is identical to that in the
476 file system.
477
479 None.
480
482 c99 , date , fort77 , pax , strip the Base Definitions volume of
483 IEEE Std 1003.1-2001, Chapter 13, Headers, <unistd.h> description of
484 {POSIX_NO_TRUNC}
485
487 Portions of this text are reprinted and reproduced in electronic form
488 from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
489 -- Portable Operating System Interface (POSIX), The Open Group Base
490 Specifications Issue 6, Copyright (C) 2001-2003 by the Institute of
491 Electrical and Electronics Engineers, Inc and The Open Group. In the
492 event of any discrepancy between this version and the original IEEE and
493 The Open Group Standard, the original IEEE and The Open Group Standard
494 is the referee document. The original Standard can be obtained online
495 at http://www.opengroup.org/unix/online.html .
496IEEE/The Open Group 2003 AR(P)