1PAX(1) BSD General Commands Manual PAX(1)
2
4 opax — read and write file archives and copy directory hierarchies (Open‐
5 BSD pax implementation)
6
8 opax [-0cdOnvz] [-f archive] [-s replstr] ... [-U user] ... [-G group]
9 ... [-T [from_date] [,to_date]] ... [pattern ...]
10 opax -r [-cdiknuvzDOYZ] [-f archive] [-o options] ... [-p string] ...
11 [-s replstr] ... [-E limit] [-U user] ... [-G group] ... [-T
12 [from_date] [,to_date]] ... [pattern ...]
13 opax -w [-0dituvzHLOPX] [-b blocksize] [[-a] [-f archive]] [-x format]
14 [-s replstr] ... [-o options] ... [-U user] ... [-G group] ...
15 [-B bytes] [-T [from_date] [,to_date] [/[c][m]]] ... [file ...]
16 opax -r -w [-0diklntuvDHLOPXYZ] [-p string] ... [-s replstr] ...
17 [-U user] ... [-G group] ... [-T [from_date] [,to_date] [/[c][m]]]
18 ... [file ...] directory
19
21 opax will read, write, and list the members of an archive file, and will
22 copy directory hierarchies. opax operation is independent of the spe‐
23 cific archive format, and supports a wide variety of different archive
24 formats. A list of supported archive formats can be found under the
25 description of the -x option.
26 The presence of the -r and the -w options specifies which of the follow‐
28 ing functional modes opax will operate under: list, read, write, and
29 copy.
30 <none> List. opax will write to standard output a table of contents of
32 the members of the archive file read from standard input, whose
33 pathnames match the specified patterns. The table of contents
34 contains one filename per line and is written using single line
35 buffering.
36 -r Read. opax extracts the members of the archive file read from
38 the standard input, with pathnames matching the specified
39 patterns. The archive format and blocking is automatically
40 determined on input. When an extracted file is a directory, the
41 entire file hierarchy rooted at that directory is extracted. All
42 extracted files are created relative to the current file hierar‐
43 chy. The setting of ownership, access and modification times,
44 and file mode of the extracted files are discussed in more detail
45 under the -p option.
46 -w Write. opax writes an archive containing the file operands to
48 standard output using the specified archive format. When no file
49 operands are specified, a list of files to copy with one per line
50 is read from standard input. When a file operand is also a
51 directory, the entire file hierarchy rooted at that directory
52 will be included.
53 -r -w Copy. opax copies the file operands to the destination
55 directory. When no file operands are specified, a list of files
56 to copy with one per line is read from the standard input. When
57 a file operand is also a directory the entire file hierarchy
58 rooted at that directory will be included. The effect of the
59 copy is as if the copied files were written to an archive file
60 and then subsequently extracted, except that there may be hard
61 links between the original and the copied files (see the -l
62 option below).
63 Warning: The destination directory must not be one of the file
65 operands or a member of a file hierarchy rooted at one of the
66 file operands. The result of a copy under these conditions is
67 unpredictable.
68 While processing a damaged archive during a read or list operation, opax
70 will attempt to recover from media defects and will search through the
71 archive to locate and process the largest number of archive members pos‐
72 sible (see the -E option for more details on error handling).
73 The directory operand specifies a destination directory pathname. If the
75 directory operand does not exist, or it is not writable by the user, or
76 it is not of type directory, opax will exit with a non-zero exit status.
77 The pattern operand is used to select one or more pathnames of archive
79 members. Archive members are selected using the pattern matching nota‐
80 tion described by fnmatch(3). When the pattern operand is not supplied,
81 all members of the archive will be selected. When a pattern matches a
82 directory, the entire file hierarchy rooted at that directory will be
83 selected. When a pattern operand does not select at least one archive
84 member, opax will write these pattern operands in a diagnostic message to
85 standard error and then exit with a non-zero exit status.
86 The file operand specifies the pathname of a file to be copied or
88 archived. When a file operand does not select at least one archive mem‐
89 ber, opax will write these file operand pathnames in a diagnostic message
90 to standard error and then exit with a non-zero exit status.
91 The options are as follows:
93 -r Read an archive file from standard input and extract the speci‐
95 fied files. If any intermediate directories are needed in order
96 to extract an archive member, these directories will be created
97 as if mkdir(2) was called with the bitwise inclusive OR of
98 S_IRWXU, S_IRWXG, and S_IRWXO as the mode argument. When the
99 selected archive format supports the specification of linked
100 files and these files cannot be linked while the archive is being
101 extracted, opax will write a diagnostic message to standard error
102 and exit with a non-zero exit status at the completion of opera‐
103 tion.
104 -w Write files to the standard output in the specified archive for‐
106 mat. When no file operands are specified, standard input is read
107 for a list of pathnames with one per line without any leading or
108 trailing ⟨blanks⟩.
109 -a Append files to the end of an archive that was previously writ‐
111 ten. If an archive format is not specified with a -x option, the
112 format currently being used in the archive will be selected. Any
113 attempt to append to an archive in a format different from the
114 format already used in the archive will cause opax to exit imme‐
115 diately with a non-zero exit status. The blocking size used in
116 the archive volume where writing starts will continue to be used
117 for the remainder of that archive volume.
118 Warning: Many storage devices are not able to support the opera‐
120 tions necessary to perform an append operation. Any attempt to
121 append to an archive stored on such a device may damage the ar‐
122 chive or have other unpredictable results. Tape drives in par‐
123 ticular are more likely to not support an append operation. An
124 archive stored in a regular file system file or on a disk device
125 will usually support an append operation.
126 -0 Use the NUL (‘\0’) character as a pathname terminator, instead of
128 newline (‘\n’). This applies only to the pathnames read from
129 standard input in the write and copy modes, and to the pathnames
130 written to standard output in list mode. This option is expected
131 to be used in concert with the -print0 function in find(1) or the
132 -0 flag in xargs(1).
133 -b blocksize
135 When writing an archive, block the output at a positive decimal
136 integer number of bytes per write to the archive file. The
137 blocksize must be a multiple of 512 bytes with a maximum of 64512
138 bytes. Archives larger than 32256 bytes violate the POSIX stan‐
139 dard and will not be portable to all systems. A blocksize can
140 end with ‘k’ or ‘b’ to specify multiplication by 1024 (1K) or
141 512, respectively. A pair of blocksizes can be separated by ‘x’
142 to indicate a product. A specific archive device may impose
143 additional restrictions on the size of blocking it will support.
144 When blocking is not specified, the default blocksize is depen‐
145 dent on the specific archive format being used (see the -x
146 option).
147 -c Match all file or archive members except those specified by the
149 pattern and file operands.
150 -d Cause files of type directory being copied or archived, or ar‐
152 chive members of type directory being extracted, to match only
153 the directory file or archive member and not the file hierarchy
154 rooted at the directory.
155 -f archive
157 Specify archive as the pathname of the input or output archive,
158 overriding the default standard input (for list and read) or
159 standard output (for write). A single archive may span multiple
160 files and different archive devices. When required, opax will
161 prompt for the pathname of the file or device of the next volume
162 in the archive.
163 -i Interactively rename files or archive members. For each archive
165 member matching a pattern operand or each file matching a file
166 operand, opax will prompt to /dev/tty giving the name of the
167 file, its file mode, and its modification time. opax will then
168 read a line from /dev/tty. If this line is blank, the file or
169 archive member is skipped. If this line consists of a single
170 period, the file or archive member is processed with no modifica‐
171 tion to its name. Otherwise, its name is replaced with the con‐
172 tents of the line. opax will immediately exit with a non-zero
173 exit status if EOF is encountered when reading a response or if
174 /dev/tty cannot be opened for reading and writing.
175 -k Do not overwrite existing files.
177 -l (The lowercase letter “ell.”) Link files. In the copy mode (-r
179 -w), hard links are made between the source and destination file
180 hierarchies whenever possible.
181 -n Select the first archive member that matches each pattern oper‐
183 and. No more than one archive member is matched for each
184 pattern. When members of type directory are matched, the file
185 hierarchy rooted at that directory is also matched (unless -d is
186 also specified).
187 -o options
189 Information to modify the algorithm for extracting or writing ar‐
190 chive files which is specific to the archive format specified by
191 -x. In general, options take the form: name=value.
192 -p string
194 Specify one or more file characteristic options (privileges).
195 The string option-argument is a string specifying file character‐
196 istics to be retained or discarded on extraction. The string
197 consists of the specification characters a, e, m, o, and p. Mul‐
198 tiple characteristics can be concatenated within the same string
199 and multiple -p options can be specified. The meaning of the
200 specification characters are as follows:
201 a Do not preserve file access times. By default, file access
203 times are preserved whenever possible.
204 e ‘Preserve everything’, the user ID, group ID, file mode bits,
206 file access time, and file modification time. This is
207 intended to be used by root, someone with all the appropriate
208 privileges, in order to preserve all aspects of the files as
209 they are recorded in the archive. The e flag is the sum of
210 the o and p flags.
211 m Do not preserve file modification times. By default, file
213 modification times are preserved whenever possible.
214 o Preserve the user ID and group ID.
216 p ‘Preserve’ the file mode bits. This is intended to be used
218 by a user with regular privileges who wants to preserve all
219 aspects of the file other than the ownership. The file times
220 are preserved by default, but two other flags are offered to
221 disable this and use the time of extraction instead.
222 In the preceding list, ‘preserve’ indicates that an attribute
224 stored in the archive is given to the extracted file, subject to
225 the permissions of the invoking process. Otherwise the attribute
226 of the extracted file is determined as part of the normal file
227 creation action. If neither the e nor the o specification char‐
228 acter is specified, or the user ID and group ID are not preserved
229 for any reason, opax will not set the S_ISUID (setuid) and
230 S_ISGID (setgid) bits of the file mode. If the preservation of
231 any of these items fails for any reason, opax will write a diag‐
232 nostic message to standard error. Failure to preserve these
233 items will affect the final exit status, but will not cause the
234 extracted file to be deleted. If the file characteristic letters
235 in any of the string option-arguments are duplicated or conflict
236 with each other, the one(s) given last will take precedence. For
237 example, if
238 -p eme
239 is specified, file modification times are still preserved.
240 -s replstr
242 Modify the file or archive member names specified by the pattern
243 or file operands according to the substitution expression
244 replstr, using the syntax of the ed(1) utility regular expres‐
245 sions. The format of these regular expressions are:
246 /old/new/[gp]
247 As in ed(1), old is a basic regular expression and new can con‐
248 tain an ampersand (‘&’), ‘\n’ (where n is a digit) back-refer‐
249 ences, or subexpression matching. The old string may also con‐
250 tain newline characters. Any non-null character can be used as a
251 delimiter (‘/’ is shown here). Multiple -s expressions can be
252 specified. The expressions are applied in the order they are
253 specified on the command line, terminating with the first suc‐
254 cessful substitution. The optional trailing g continues to apply
255 the substitution expression to the pathname substring which
256 starts with the first character following the end of the last
257 successful substitution. The first unsuccessful substitution
258 stops the operation of the g option. The optional trailing p
259 will cause the final result of a successful substitution to be
260 written to standard error in the following format:
261 <original pathname> >> <new pathname>
262 File or archive member names that substitute to the empty string
263 are not selected and will be skipped.
264 -t Reset the access times of any file or directory read or accessed
266 by opax to be the same as they were before being read or accessed
267 by opax.
268 -u Ignore files that are older (having a less recent file modifica‐
270 tion time) than a pre-existing file or archive member with the
271 same name. During read, an archive member with the same name as
272 a file in the file system will be extracted if the archive member
273 is newer than the file. During write, a file system member with
274 the same name as an archive member will be written to the archive
275 if it is newer than the archive member. During copy, the file in
276 the destination hierarchy is replaced by the file in the source
277 hierarchy or by a link to the file in the source hierarchy if the
278 file in the source hierarchy is newer.
279 -v During a list operation, produce a verbose table of contents
281 using the format of the ls(1) utility with the -l option. For
282 pathnames representing a hard link to a previous member of the
283 archive, the output has the format:
284 <ls -l listing> == <link name>
285 For pathnames representing a symbolic link, the output has the
286 format:
287 <ls -l listing> => <link name>
288 Where <ls -l listing> is the output format specified by the ls(1)
289 utility when used with the -l option. Otherwise for all the
290 other operational modes (read, write, and copy), pathnames are
291 written and flushed to standard error without a trailing newline
292 as soon as processing begins on that file or archive member. The
293 trailing newline is not buffered and is written only after the
294 file has been read or written.
295 -x format
297 Specify the output archive format, with the default format being
298 ustar. opax currently supports the following formats:
299 cpio The extended cpio interchange format specified in the
301 IEEE Std 1003.2 (“POSIX.2”) standard. The default
302 blocksize for this format is 5120 bytes. Inode and
303 device information about a file (used for detecting file
304 hard links by this format) which may be truncated by
305 this format is detected by opax and is repaired.
306 bcpio The old binary cpio format. The default blocksize for
308 this format is 5120 bytes. This format is not very por‐
309 table and should not be used when other formats are
310 available. Inode and device information about a file
311 (used for detecting file hard links by this format)
312 which may be truncated by this format is detected by
313 opax and is repaired.
314 sv4cpio The System V release 4 cpio. The default blocksize for
316 this format is 5120 bytes. Inode and device information
317 about a file (used for detecting file hard links by this
318 format) which may be truncated by this format is
319 detected by opax and is repaired.
320 sv4crc The System V release 4 cpio with file crc checksums.
322 The default blocksize for this format is 5120 bytes.
323 Inode and device information about a file (used for
324 detecting file hard links by this format) which may be
325 truncated by this format is detected by opax and is
326 repaired.
327 tar The old BSD tar format as found in BSD4.3. The default
329 blocksize for this format is 10240 bytes. Pathnames
330 stored by this format must be 100 characters or less in
331 length (including the trailing character, which means
332 that filenames can have a maximum length of 99 charac‐
333 ters). Only regular files, hard links, soft links, and
334 directories will be archived (other file system types
335 are not supported). For backwards compatibility with
336 even older tar formats, a -o option can be used when
337 writing an archive to omit the storage of directories.
338 This option takes the form:
339 -o write_opt=nodir
340 ustar The extended tar interchange format specified in the
342 IEEE Std 1003.2 (“POSIX.2”) standard. The default
343 blocksize for this format is 10240 bytes. Filenames
344 stored by this format must be 100 characters or less in
345 length (including the trailing character, which means
346 that filenames can have a maximum length of 99 charac‐
347 ters). Pathnames (directorynames + filenames) stored by
348 this format must be 250 characters or less in length.
349 opax will detect and report any file that it is unable to store
351 or extract as the result of any specific archive format restric‐
352 tions. The individual archive formats may impose additional
353 restrictions on use. Typical archive format restrictions include
354 (but are not limited to): file pathname length, file size, link
355 pathname length, and the type of the file.
356 -z Use gzip(1) to compress (decompress) the archive while writing
358 (reading). Incompatible with -a.
359 -B bytes
361 Limit the number of bytes written to a single archive volume to
362 bytes. The bytes limit can end with ‘m’, ‘k’, or ‘b’ to specify
363 multiplication by 1048576 (1M), 1024 (1K) or 512, respectively.
364 A pair of bytes limits can be separated by ‘x’ to indicate a
365 product.
366 Warning: Only use this option when writing an archive to a device
368 which supports an end of file read condition based on last (or
369 largest) write offset (such as a regular file or a tape drive).
370 The use of this option with a floppy or hard disk is not recom‐
371 mended.
372 -D This option is the same as the -u option, except that the file
374 inode change time is checked instead of the file modification
375 time. The file inode change time can be used to select files
376 whose inode information (e.g., UID, GID, etc.) is newer than a
377 copy of the file in the destination directory.
378 -E limit
380 Limit the number of consecutive read faults while trying to read
381 a flawed archive to limit. With a positive limit, opax will
382 attempt to recover from an archive read error and will continue
383 processing starting with the next file stored in the archive. A
384 limit of 0 will cause opax to stop operation after the first read
385 error is detected on an archive volume. A limit of NONE will
386 cause opax to attempt to recover from read errors forever. The
387 default limit is a small positive number of retries.
388 Warning: Using this option with NONE should be used with extreme
390 caution as opax may get stuck in an infinite loop on a very badly
391 flawed archive.
392 -G group
394 Select a file based on its group name, or when starting with a #,
395 a numeric gid. A ‘\’ can be used to escape the #. Multiple -G
396 options may be supplied and checking stops with the first match.
397 -H Follow only command-line symbolic links while performing a physi‐
399 cal file system traversal.
400 -L Follow all symbolic links to perform a logical file system tra‐
402 versal.
403 -O Force the archive to be one volume. If a volume ends prema‐
405 turely, opax will not prompt for a new volume. This option can
406 be useful for automated tasks where error recovery cannot be per‐
407 formed by a human.
408 -P Do not follow symbolic links, perform a physical file system tra‐
410 versal. This is the default mode.
411 -T [from_date][,to_date][/[c][m]]
413 Allow files to be selected based on a file modification or inode
414 change time falling within a specified time range of from_date to
415 to_date (the dates are inclusive). If only a from_date is sup‐
416 plied, all files with a modification or inode change time equal
417 to or younger are selected. If only a to_date is supplied, all
418 files with a modification or inode change time equal to or older
419 will be selected. When the from_date is equal to the to_date,
420 only files with a modification or inode change time of exactly
421 that time will be selected.
422 When opax is in the write or copy mode, the optional trailing
424 field [c][m] can be used to determine which file time (inode
425 change, file modification or both) are used in the comparison.
426 If neither is specified, the default is to use file modification
427 time only. The m specifies the comparison of file modification
428 time (the time when the file was last written). The c specifies
429 the comparison of inode change time (the time when the file inode
430 was last changed; e.g., a change of owner, group, mode, etc).
431 When c and m are both specified, then the modification and inode
432 change times are both compared. The inode change time comparison
433 is useful in selecting files whose attributes were recently
434 changed or selecting files which were recently created and had
435 their modification time reset to an older time (as what happens
436 when a file is extracted from an archive and the modification
437 time is preserved). Time comparisons using both file times is
438 useful when opax is used to create a time based incremental ar‐
439 chive (only files that were changed during a specified time range
440 will be archived).
441 A time range is made up of six different fields and each field
443 must contain two digits. The format is:
444 [[[[[cc]yy]mm]dd]HH]MM[.SS]
445 Where cc is the first two digits of the year (the century), yy is
446 the last two digits of the year, the first mm is the month (from
447 01 to 12), dd is the day of the month (from 01 to 31), HH is the
448 hour of the day (from 00 to 23), MM is the minute (from 00 to
449 59), and SS is the seconds (from 00 to 59). The minute field MM
450 is required, while the other fields are optional and must be
451 added in the following order:
452 HH, dd, mm, yy, cc.
453 The SS field may be added independently of the other fields.
454 Time ranges are relative to the current time, so
455 -T 1234/cm
456 would select all files with a modification or inode change time
457 of 12:34 PM today or later. Multiple -T time range can be sup‐
458 plied and checking stops with the first match.
459 -U user
461 Select a file based on its user name, or when starting with a #,
462 a numeric UID. A ‘\’ can be used to escape the #. Multiple -U
463 options may be supplied and checking stops with the first match.
464 -X When traversing the file hierarchy specified by a pathname, do
466 not descend into directories that have a different device ID.
467 See the st_dev field as described in stat(2) for more information
468 about device IDs.
469 -Y This option is the same as the -D option, except that the inode
471 change time is checked using the pathname created after all the
472 file name modifications have completed.
473 -Z This option is the same as the -u option, except that the modifi‐
475 cation time is checked using the pathname created after all the
476 file name modifications have completed.
477 The options that operate on the names of files or archive members (-c,
479 -i, -n, -s, -u, -v, -D, -G, -T, -U, -Y, and -Z) interact as follows.
480 When extracting files during a read operation, archive members are
482 ‘selected’, based only on the user specified pattern operands as modified
483 by the -c, -n, -u, -D, -G, -T, -U options. Then any -s and -i options
484 will modify in that order, the names of these selected files. Then the
485 -Y and -Z options will be applied based on the final pathname. Finally,
486 the -v option will write the names resulting from these modifications.
487 When archiving files during a write operation, or copying files during a
489 copy operation, archive members are ‘selected’, based only on the user
490 specified pathnames as modified by the -n, -u, -D, -G, -T, and -U options
491 (the -D option only applies during a copy operation). Then any -s and -i
492 options will modify in that order, the names of these selected files.
493 Then during a copy operation the -Y and the -Z options will be applied
494 based on the final pathname. Finally, the -v option will write the names
495 resulting from these modifications.
496 When one or both of the -u or -D options are specified along with the -n
498 option, a file is not considered selected unless it is newer than the
499 file to which it is compared.
500
502 TMPDIR Path in which to store temporary files.
503
505 $ opax -w -f /dev/rst0 .
506 Copies the contents of the current directory to the device /dev/rst0.
508 $ opax -v -f filename
510 Gives the verbose table of contents for an archive stored in filename.
512 $ mkdir newdir; cd olddir; opax -rw . newdir
514 This sequence of commands will copy the entire olddir directory hierarchy
516 to newdir.
517 $ opax -r -s ',^//*usr//*,,' -f a.pax
519 Reads the archive a.pax, with all files rooted in /usr into the archive
521 extracted relative to the current directory.
522 $ opax -rw -i . dest_dir
524 Can be used to interactively select the files to copy from the current
526 directory to dest_dir.
527 $ opax -r -pe -U root -G bin -f a.pax
529 Extract all files from the archive a.pax which are owned by root with
531 group bin and preserve all file permissions.
532 $ opax -r -w -v -Y -Z home /backup"
534 Update (and list) only those files in the destination directory /backup
536 which are older (less recent inode change or file modification times)
537 than files with the same name found in the source file tree home.
538
540 opax will exit with one of the following values:
541 0 All files were processed successfully.
543 1 An error occurred.
545 Whenever opax cannot create a file or a link when reading an archive or
547 cannot find a file when writing an archive, or cannot preserve the user
548 ID, group ID, or file mode when the -p option is specified, a diagnostic
549 message is written to standard error and a non-zero exit status will be
550 returned, but processing will continue. In the case where opax cannot
551 create a link to a file, opax will not create a second copy of the file.
552 If the extraction of a file from an archive is prematurely terminated by
554 a signal or error, opax may have only partially extracted a file the user
555 wanted. Additionally, the file modes of extracted files and directories
556 may have incorrect file bits, and the modification and access times may
557 be wrong.
558 If the creation of an archive is prematurely terminated by a signal or
560 error, opax may have only partially created the archive which may violate
561 the specific archive format specification.
562 If while doing a copy, opax detects a file is about to overwrite itself,
564 the file is not copied, a diagnostic message is written to standard error
565 and when opax completes it will exit with a non-zero exit status.
566
568 spax(1), tar(1), bsdtar(1), star(1), cpio(1), bsdcpio(1), scpio(1)
569
571 The opax utility is a superset of the IEEE Std 1003.2 (“POSIX.2”) stan‐
572 dard. The options -B, -D, -E, -G, -H, -L, -O, -P, -T, -U, -Y, -Z, the
573 archive formats bcpio, sv4cpio, sv4crc, tar, and the flawed archive han‐
574 dling during list and read operations are extensions to the POSIX stan‐
575 dard.
576
578 Keith Muller at the University of California, San Diego.
579BSD April 18, 1994 BSD