1BSDTAR(1) BSD General Commands Manual BSDTAR(1)
2
4 bsdtar — manipulate tape archives
5
7 bsdtar [bundled-flags ⟨args⟩] [⟨file⟩ | ⟨pattern⟩ ...]
8 bsdtar {-c} [options] [files | directories]
9 bsdtar {-r | -u} -f archive-file [options] [files | directories]
10 bsdtar {-t | -x} [options] [patterns]
11
13 bsdtar creates and manipulates streaming archive files. This implementa‐
14 tion can extract from tar, pax, cpio, zip, jar, ar, xar, rpm, 7-zip, and
15 ISO 9660 cdrom images and can create tar, pax, cpio, ar, zip, 7-zip, and
16 shar archives.
17
18 The first synopsis form shows a “bundled” option word. This usage is
19 provided for compatibility with historical implementations. See COMPATI‐
20 BILITY below for details.
21
22 The other synopsis forms show the preferred usage. The first option to
23 bsdtar is a mode indicator from the following list:
24 -c Create a new archive containing the specified items. The long
25 option form is --create.
26 -r Like -c, but new entries are appended to the archive. Note that
27 this only works on uncompressed archives stored in regular files.
28 The -f option is required. The long option form is --append.
29 -t List archive contents to stdout. The long option form is --list.
30 -u Like -r, but new entries are added only if they have a modifica‐
31 tion date newer than the corresponding entry in the archive.
32 Note that this only works on uncompressed archives stored in reg‐
33 ular files. The -f option is required. The long form is
34 --update.
35 -x Extract to disk from the archive. If a file with the same name
36 appears more than once in the archive, each copy will be
37 extracted, with later copies overwriting (replacing) earlier
38 copies. The long option form is --extract.
39
40 In -c, -r, or -u mode, each specified file or directory is added to the
41 archive in the order specified on the command line. By default, the con‐
42 tents of each directory are also archived.
43
44 In extract or list mode, the entire command line is read and parsed
45 before the archive is opened. The pathnames or patterns on the command
46 line indicate which items in the archive should be processed. Patterns
47 are shell-style globbing patterns as documented in tcsh(1).
48
50 Unless specifically stated otherwise, options are applicable in all oper‐
51 ating modes.
52
53 @archive
54 (c and r modes only) The specified archive is opened and the
55 entries in it will be appended to the current archive. As a sim‐
56 ple example,
57 bsdtar -c -f - newfile @original.tar
58 writes a new archive to standard output containing a file newfile
59 and all of the entries from original.tar. In contrast,
60 bsdtar -c -f - newfile original.tar
61 creates a new archive with only two entries. Similarly,
62 bsdtar -czf - --format pax @-
63 reads an archive from standard input (whose format will be deter‐
64 mined automatically) and converts it into a gzip-compressed pax-
65 format archive on stdout. In this way, bsdtar can be used to
66 convert archives from one format to another.
67
68 -a, --auto-compress
69 (c mode only) Use the archive suffix to decide a set of the for‐
70 mat and the compressions. As a simple example,
71 bsdtar -a -cf archive.tgz source.c source.h
72 creates a new archive with restricted pax format and gzip com‐
73 pression,
74 bsdtar -a -cf archive.tar.bz2.uu source.c source.h
75 creates a new archive with restricted pax format and bzip2 com‐
76 pression and uuencode compression,
77 bsdtar -a -cf archive.zip source.c source.h
78 creates a new archive with zip format,
79 bsdtar -a -jcf archive.tgz source.c source.h
80 ignores the “-j” option, and creates a new archive with
81 restricted pax format and gzip compression,
82 bsdtar -a -jcf archive.xxx source.c source.h
83 if it is unknown suffix or no suffix, creates a new archive with
84 restricted pax format and bzip2 compression.
85
86 --acls (c, r, u, x modes only) Archive or extract POSIX.1e or NFSv4
87 ACLs. This is the reverse of --no-acls and the default behavior
88 in c, r, and u modes (except on Mac OS X) or if bsdtar is run in
89 x mode as root. On Mac OS X this option translates extended ACLs
90 to NFSv4 ACLs. To store extended ACLs the --mac-metadata option
91 is preferred.
92
93 -B, --read-full-blocks
94 Ignored for compatibility with other tar(1) implementations.
95
96 -b blocksize, --block-size blocksize
97 Specify the block size, in 512-byte records, for tape drive I/O.
98 As a rule, this argument is only needed when reading from or
99 writing to tape drives, and usually not even then as the default
100 block size of 20 records (10240 bytes) is very common.
101
102 -C directory, --cd directory, --directory directory
103 In c and r mode, this changes the directory before adding the
104 following files. In x mode, change directories after opening the
105 archive but before extracting entries from the archive.
106
107 --chroot
108 (x mode only) chroot() to the current directory after processing
109 any -C options and before extracting any files.
110
111 --clear-nochange-fflags
112 (x mode only) Before removing file system objects to replace
113 them, clear platform-specific file flags that might prevent
114 removal.
115
116 --exclude pattern
117 Do not process files or directories that match the specified pat‐
118 tern. Note that exclusions take precedence over patterns or
119 filenames specified on the command line.
120
121 --fflags
122 (c, r, u, x modes only) Archive or extract file flags. This is
123 the reverse of --no-fflags and the default behavior in c, r, and
124 u modes or if bsdtar is run in x mode as root.
125
126 --format format
127 (c, r, u mode only) Use the specified format for the created ar‐
128 chive. Supported formats include “cpio”, “pax”, “shar”, and
129 “ustar”. Other formats may also be supported; see
130 libarchive-formats(5) for more information about currently-sup‐
131 ported formats. In r and u modes, when extending an existing ar‐
132 chive, the format specified here must be compatible with the for‐
133 mat of the existing archive on disk.
134
135 -f file, --file file
136 Read the archive from or write the archive to the specified file.
137 The filename can be - for standard input or standard output. The
138 default varies by system; on FreeBSD, the default is /dev/sa0; on
139 Linux, the default is /dev/st0.
140
141 --gid id
142 Use the provided group id number. On extract, this overrides the
143 group id in the archive; the group name in the archive will be
144 ignored. On create, this overrides the group id read from disk;
145 if --gname is not also specified, the group name will be set to
146 match the group id.
147
148 --gname name
149 Use the provided group name. On extract, this overrides the
150 group name in the archive; if the provided group name does not
151 exist on the system, the group id (from the archive or from the
152 --gid option) will be used instead. On create, this sets the
153 group name that will be stored in the archive; the name will not
154 be verified against the system group database.
155
156 -H (c and r modes only) Symbolic links named on the command line
157 will be followed; the target of the link will be archived, not
158 the link itself.
159
160 -h (c and r modes only) Synonym for -L.
161
162 -I Synonym for -T.
163
164 --help Show usage.
165
166 --hfsCompression
167 (x mode only) Mac OS X specific (v10.6 or later). Compress
168 extracted regular files with HFS+ compression.
169
170 --ignore-zeros
171 An alias of --options read_concatenated_archives for compatibil‐
172 ity with GNU tar.
173
174 --include pattern
175 Process only files or directories that match the specified pat‐
176 tern. Note that exclusions specified with --exclude take prece‐
177 dence over inclusions. If no inclusions are explicitly speci‐
178 fied, all entries are processed by default. The --include option
179 is especially useful when filtering archives. For example, the
180 command
181 bsdtar -c -f new.tar --include='*foo*' @old.tgz
182 creates a new archive new.tar containing only the entries from
183 old.tgz containing the string ‘foo’.
184
185 -J, --xz
186 (c mode only) Compress the resulting archive with xz(1). In
187 extract or list modes, this option is ignored. Note that, unlike
188 other tar implementations, this implementation recognizes XZ com‐
189 pression automatically when reading archives.
190
191 -j, --bzip, --bzip2, --bunzip2
192 (c mode only) Compress the resulting archive with bzip2(1). In
193 extract or list modes, this option is ignored. Note that, unlike
194 other tar implementations, this implementation recognizes bzip2
195 compression automatically when reading archives.
196
197 -k, --keep-old-files
198 (x mode only) Do not overwrite existing files. In particular, if
199 a file appears more than once in an archive, later copies will
200 not overwrite earlier copies.
201
202 --keep-newer-files
203 (x mode only) Do not overwrite existing files that are newer than
204 the versions appearing in the archive being extracted.
205
206 -L, --dereference
207 (c and r modes only) All symbolic links will be followed. Nor‐
208 mally, symbolic links are archived as such. With this option,
209 the target of the link will be archived instead.
210
211 -l, --check-links
212 (c and r modes only) Issue a warning message unless all links to
213 each file are archived.
214
215 --lrzip
216 (c mode only) Compress the resulting archive with lrzip(1). In
217 extract or list modes, this option is ignored.
218
219 --lz4 (c mode only) Compress the archive with lz4-compatible compres‐
220 sion before writing it. In input mode, this option is ignored;
221 lz4 compression is recognized automatically on input.
222
223 --lzma (c mode only) Compress the resulting archive with the original
224 LZMA algorithm. Use of this option is discouraged and new ar‐
225 chives should be created with --xz instead. Note that, unlike
226 other tar implementations, this implementation recognizes LZMA
227 compression automatically when reading archives.
228
229 --lzop (c mode only) Compress the resulting archive with lzop(1). In
230 extract or list modes, this option is ignored.
231
232 -m, --modification-time
233 (x mode only) Do not extract modification time. By default, the
234 modification time is set to the time stored in the archive.
235
236 --mac-metadata
237 (c, r, u and x mode only) Mac OS X specific. Archive or extract
238 extended ACLs and extended attributes using copyfile(3) in Apple‐
239 Double format. This is the reverse of --no-mac-metadata. and the
240 default behavior in c, r, and u modes or if bsdtar is run in x
241 mode as root.
242
243 -n, --norecurse, --no-recursion
244 (c, r, u modes only) Do not recursively archive the contents of
245 directories.
246
247 --newer date
248 (c, r, u modes only) Only include files and directories newer
249 than the specified date. This compares ctime entries.
250
251 --newer-mtime date
252 (c, r, u modes only) Like --newer, except it compares mtime
253 entries instead of ctime entries.
254
255 --newer-than file
256 (c, r, u modes only) Only include files and directories newer
257 than the specified file. This compares ctime entries.
258
259 --newer-mtime-than file
260 (c, r, u modes only) Like --newer-than, except it compares mtime
261 entries instead of ctime entries.
262
263 --nodump
264 (c and r modes only) Honor the nodump file flag by skipping this
265 file.
266
267 --nopreserveHFSCompression
268 (x mode only) Mac OS X specific (v10.6 or later). Do not compress
269 extracted regular files which were compressed with HFS+ compres‐
270 sion before archived. By default, compress the regular files
271 again with HFS+ compression.
272
273 --null (use with -I or -T) Filenames or patterns are separated by null
274 characters, not by newlines. This is often used to read file‐
275 names output by the -print0 option to find(1).
276
277 --no-acls
278 (c, r, u, x modes only) Do not archive or extract POSIX.1e or
279 NFSv4 ACLs. This is the reverse of --acls and the default behav‐
280 ior if bsdtar is run as non-root in x mode (on Mac OS X as any
281 user in c, r, u and x modes).
282
283 --no-fflags
284 (c, r, u, x modes only) Do not archive or extract file flags.
285 This is the reverse of --fflags and the default behavior if
286 bsdtar is run as non-root in x mode.
287
288 --no-mac-metadata
289 (x mode only) Mac OS X specific. Do not archive or extract ACLs
290 and extended attributes using copyfile(3) in AppleDouble format.
291 This is the reverse of --mac-metadata. and the default behavior
292 if bsdtar is run as non-root in x mode.
293
294 -n, --norecurse, --no-recursion
295
296 --no-same-owner
297 (x mode only) Do not extract owner and group IDs. This is the
298 reverse of --same-owner and the default behavior if bsdtar is run
299 as non-root.
300
301 --no-same-permissions
302 (x mode only) Do not extract full permissions (SGID, SUID, sticky
303 bit, ACLs, extended attributes or extended file flags). This is
304 the reverse of -p and the default behavior if bsdtar is run as
305 non-root.
306
307 --no-xattrs
308 (c, r, u, x modes only) Do not archive or extract extended
309 attributes. This is the reverse of --xattrs and the default
310 behavior if bsdtar is run as non-root in x mode.
311
312 --numeric-owner
313 This is equivalent to --uname "" --gname "". On extract, it
314 causes user and group names in the archive to be ignored in favor
315 of the numeric user and group ids. On create, it causes user and
316 group names to not be stored in the archive.
317
318 -O, --to-stdout
319 (x, t modes only) In extract (-x) mode, files will be written to
320 standard out rather than being extracted to disk. In list (-t)
321 mode, the file listing will be written to stderr rather than the
322 usual stdout.
323
324 -o (x mode) Use the user and group of the user running the program
325 rather than those specified in the archive. Note that this has
326 no significance unless -p is specified, and the program is being
327 run by the root user. In this case, the file modes and flags
328 from the archive will be restored, but ACLs or owner information
329 in the archive will be discarded.
330
331 -o (c, r, u mode) A synonym for --format ustar
332
333 --older date
334 (c, r, u modes only) Only include files and directories older
335 than the specified date. This compares ctime entries.
336
337 --older-mtime date
338 (c, r, u modes only) Like --older, except it compares mtime
339 entries instead of ctime entries.
340
341 --older-than file
342 (c, r, u modes only) Only include files and directories older
343 than the specified file. This compares ctime entries.
344
345 --older-mtime-than file
346 (c, r, u modes only) Like --older-than, except it compares mtime
347 entries instead of ctime entries.
348
349 --one-file-system
350 (c, r, and u modes) Do not cross mount points.
351
352 --options options
353 Select optional behaviors for particular modules. The argument
354 is a text string containing comma-separated keywords and values.
355 These are passed to the modules that handle particular formats to
356 control how those formats will behave. Each option has one of
357 the following forms:
358 key=value
359 The key will be set to the specified value in every mod‐
360 ule that supports it. Modules that do not support this
361 key will ignore it.
362 key The key will be enabled in every module that supports it.
363 This is equivalent to key=1.
364 !key The key will be disabled in every module that supports
365 it.
366 module:key=value, module:key, module:!key
367 As above, but the corresponding key and value will be
368 provided only to modules whose name matches module.
369 The currently supported modules and keys are:
370 iso9660:joliet
371 Support Joliet extensions. This is enabled by default,
372 use !joliet or iso9660:!joliet to disable.
373 iso9660:rockridge
374 Support Rock Ridge extensions. This is enabled by
375 default, use !rockridge or iso9660:!rockridge to disable.
376 gzip:compression-level
377 A decimal integer from 1 to 9 specifying the gzip com‐
378 pression level.
379 gzip:timestamp
380 Store timestamp. This is enabled by default, use
381 !timestamp or gzip:!timestamp to disable.
382 lrzip:compression=type
383 Use type as compression method. Supported values are
384 bzip2, gzip, lzo (ultra fast), and zpaq (best, extremely
385 slow).
386 lrzip:compression-level
387 A decimal integer from 1 to 9 specifying the lrzip com‐
388 pression level.
389 lz4:compression-level
390 A decimal integer from 1 to 9 specifying the lzop com‐
391 pression level.
392 lz4:stream-checksum
393 Enable stream checksum. This is by default, use
394 lz4:!stream-checksum to disable.
395 lz4:block-checksum
396 Enable block checksum (Disabled by default).
397 lz4:block-size
398 A decimal integer from 4 to 7 specifying the lz4 compres‐
399 sion block size (7 is set by default).
400 lz4:block-dependence
401 Use the previous block of the block being compressed for
402 a compression dictionary to improve compression ratio.
403 lzop:compression-level
404 A decimal integer from 1 to 9 specifying the lzop com‐
405 pression level.
406 xz:compression-level
407 A decimal integer from 0 to 9 specifying the xz compres‐
408 sion level.
409 mtree:keyword
410 The mtree writer module allows you to specify which mtree
411 keywords will be included in the output. Supported key‐
412 words include: cksum, device, flags, gid, gname, indent,
413 link, md5, mode, nlink, rmd160, sha1, sha256, sha384,
414 sha512, size, time, uid, uname. The default is equiva‐
415 lent to: “device, flags, gid, gname, link, mode, nlink,
416 size, time, type, uid, uname”.
417 mtree:all
418 Enables all of the above keywords. You can also use
419 mtree:!all to disable all keywords.
420 mtree:use-set
421 Enable generation of /set lines in the output.
422 mtree:indent
423 Produce human-readable output by indenting options and
424 splitting lines to fit into 80 columns.
425 zip:compression=type
426 Use type as compression method. Supported values are
427 store (uncompressed) and deflate (gzip algorithm).
428 zip:encryption
429 Enable encryption using traditional zip encryption.
430 zip:encryption=type
431 Use type as encryption type. Supported values are
432 zipcrypt (traditional zip encryption), aes128 (WinZip
433 AES-128 encryption) and aes256 (WinZip AES-256 encryp‐
434 tion).
435 read_concatenated_archives
436 Ignore zeroed blocks in the archive, which occurs when
437 multiple tar archives have been concatenated together.
438 Without this option, only the contents of the first con‐
439 catenated archive would be read. This option is compara‐
440 ble to the -i, --ignore-zeros option of GNU tar.
441 If a provided option is not supported by any module, that is a
442 fatal error.
443
444 -P, --absolute-paths
445 Preserve pathnames. By default, absolute pathnames (those that
446 begin with a / character) have the leading slash removed both
447 when creating archives and extracting from them. Also, bsdtar
448 will refuse to extract archive entries whose pathnames contain ..
449 or whose target directory would be altered by a symlink. This
450 option suppresses these behaviors.
451
452 -p, --insecure, --preserve-permissions
453 (x mode only) Preserve file permissions. Attempt to restore the
454 full permissions, including owner, file modes, ACLs, extended
455 attributes and extended file flags, if available, for each item
456 extracted from the archive. This is te reverse of
457 --no-same-permissions and the default if bsdtar is being run by
458 root and can be partially overridden by also specifying
459 --no-acls, --no-fflags, --no-mac-metadata or --no-xattrs.
460
461 --passphrase passphrase
462 The passphrase is used to extract or create an encrypted archive.
463 Currently, zip is the only supported format that supports encryp‐
464 tion. You shouldn't use this option unless you realize how inse‐
465 cure use of this option is.
466
467 --posix
468 (c, r, u mode only) Synonym for --format pax
469
470 -q, --fast-read
471 (x and t mode only) Extract or list only the first archive entry
472 that matches each pattern or filename operand. Exit as soon as
473 each specified pattern or filename has been matched. By default,
474 the archive is always read to the very end, since there can be
475 multiple entries with the same name and, by convention, later
476 entries overwrite earlier entries. This option is provided as a
477 performance optimization.
478
479 -S (x mode only) Extract files as sparse files. For every block on
480 disk, check first if it contains only NULL bytes and seek over it
481 otherwise. This works similar to the conv=sparse option of dd.
482
483 -s pattern
484 Modify file or archive member names according to pattern. The
485 pattern has the format /old/new/[ghHprRsS] where old is a basic
486 regular expression, new is the replacement string of the matched
487 part, and the optional trailing letters modify how the replace‐
488 ment is handled. If old is not matched, the pattern is skipped.
489 Within new, ~ is substituted with the match, \1 to \9 with the
490 content of the corresponding captured group. The optional trail‐
491 ing g specifies that matching should continue after the matched
492 part and stop on the first unmatched pattern. The optional
493 trailing s specifies that the pattern applies to the value of
494 symbolic links. The optional trailing p specifies that after a
495 successful substitution the original path name and the new path
496 name should be printed to standard error. Optional trailing H,
497 R, or S characters suppress substitutions for hardlink targets,
498 regular filenames, or symlink targets, respectively. Optional
499 trailing h, r, or s characters enable substitutions for hardlink
500 targets, regular filenames, or symlink targets, respectively.
501 The default is hrs which applies substitutions to all names. In
502 particular, it is never necessary to specify h, r, or s.
503
504 --same-owner
505 (x mode only) Extract owner and group IDs. This is the reverse
506 of --no-same-owner and the default behavior if bsdtar is run as
507 root.
508
509 --strip-components count
510 Remove the specified number of leading path elements. Pathnames
511 with fewer elements will be silently skipped. Note that the
512 pathname is edited after checking inclusion/exclusion patterns
513 but before security checks.
514
515 -T filename, --files-from filename
516 In x or t mode, bsdtar will read the list of names to be
517 extracted from filename. In c mode, bsdtar will read names to be
518 archived from filename. The special name “-C” on a line by
519 itself will cause the current directory to be changed to the
520 directory specified on the following line. Names are terminated
521 by newlines unless --null is specified. Note that --null also
522 disables the special handling of lines containing “-C”. Note:
523 If you are generating lists of files using find(1), you probably
524 want to use -n as well.
525
526 --totals
527 (c, r, u modes only) After archiving all files, print a summary
528 to stderr.
529
530 -U, --unlink, --unlink-first
531 (x mode only) Unlink files before creating them. This can be a
532 minor performance optimization if most files already exist, but
533 can make things slower if most files do not already exist. This
534 flag also causes bsdtar to remove intervening directory symlinks
535 instead of reporting an error. See the SECURITY section below
536 for more details.
537
538 --uid id
539 Use the provided user id number and ignore the user name from the
540 archive. On create, if --uname is not also specified, the user
541 name will be set to match the user id.
542
543 --uname name
544 Use the provided user name. On extract, this overrides the user
545 name in the archive; if the provided user name does not exist on
546 the system, it will be ignored and the user id (from the archive
547 or from the --uid option) will be used instead. On create, this
548 sets the user name that will be stored in the archive; the name
549 is not verified against the system user database.
550
551 --use-compress-program program
552 Pipe the input (in x or t mode) or the output (in c mode) through
553 program instead of using the builtin compression support.
554
555 -v, --verbose
556 Produce verbose output. In create and extract modes, bsdtar will
557 list each file name as it is read from or written to the archive.
558 In list mode, bsdtar will produce output similar to that of
559 ls(1). An additional -v option will also provide ls-like details
560 in create and extract mode.
561
562 --version
563 Print version of bsdtar and libarchive, and exit.
564
565 -w, --confirmation, --interactive
566 Ask for confirmation for every action.
567
568 -X filename, --exclude-from filename
569 Read a list of exclusion patterns from the specified file. See
570 --exclude for more information about the handling of exclusions.
571
572 --xattrs
573 (c, r, u, x modes only) Archive or extract extended attributes.
574 This is the reverse of --no-xattrs and the default behavior in c,
575 r, and u modes or if bsdtar is run in x mode as root.
576
577 -y (c mode only) Compress the resulting archive with bzip2(1). In
578 extract or list modes, this option is ignored. Note that, unlike
579 other tar implementations, this implementation recognizes bzip2
580 compression automatically when reading archives.
581
582 -Z, --compress, --uncompress
583 (c mode only) Compress the resulting archive with compress(1).
584 In extract or list modes, this option is ignored. Note that,
585 unlike other tar implementations, this implementation recognizes
586 compress compression automatically when reading archives.
587
588 -z, --gunzip, --gzip
589 (c mode only) Compress the resulting archive with gzip(1). In
590 extract or list modes, this option is ignored. Note that, unlike
591 other tar implementations, this implementation recognizes gzip
592 compression automatically when reading archives.
593
595 The following environment variables affect the execution of bsdtar:
596
597 TAR_READER_OPTIONS
598 The default options for format readers and compression read‐
599 ers. The --options option overrides this.
600
601 TAR_WRITER_OPTIONS
602 The default options for format writers and compression writ‐
603 ers. The --options option overrides this.
604
605 LANG The locale to use. See environ(7) for more information.
606
607 TAPE The default device. The -f option overrides this. Please see
608 the description of the -f option above for more details.
609
610 TZ The timezone to use when displaying dates. See environ(7) for
611 more information.
612
614 The bsdtar utility exits 0 on success, and >0 if an error occurs.
615
617 The following creates a new archive called file.tar.gz that contains two
618 files source.c and source.h:
619 bsdtar -czf file.tar.gz source.c source.h
620
621 To view a detailed table of contents for this archive:
622 bsdtar -tvf file.tar.gz
623
624 To extract all entries from the archive on the default tape drive:
625 bsdtar -x
626
627 To examine the contents of an ISO 9660 cdrom image:
628 bsdtar -tf image.iso
629
630 To move file hierarchies, invoke bsdtar as
631 bsdtar -cf - -C srcdir . | bsdtar -xpf - -C destdir
632 or more traditionally
633 cd srcdir ; bsdtar -cf - . | (cd destdir ; bsdtar -xpf -)
634
635 In create mode, the list of files and directories to be archived can also
636 include directory change instructions of the form -Cfoo/baz and archive
637 inclusions of the form @archive-file. For example, the command line
638 bsdtar -c -f new.tar foo1 @old.tgz -C/tmp foo2
639 will create a new archive new.tar. bsdtar will read the file foo1 from
640 the current directory and add it to the output archive. It will then
641 read each entry from old.tgz and add those entries to the output archive.
642 Finally, it will switch to the /tmp directory and add foo2 to the output
643 archive.
644
645 An input file in mtree(5) format can be used to create an output archive
646 with arbitrary ownership, permissions, or names that differ from existing
647 data on disk:
648
649 $ cat input.mtree
650 #mtree
651 usr/bin uid=0 gid=0 mode=0755 type=dir
652 usr/bin/ls uid=0 gid=0 mode=0755 type=file content=myls
653 $ tar -cvf output.tar @input.mtree
654
655 The --newer and --newer-mtime switches accept a variety of common date
656 and time specifications, including “12 Mar 2005 7:14:29pm”, “2005-03-12
657 19:14”, “5 minutes ago”, and “19:14 PST May 1”.
658
659 The --options argument can be used to control various details of archive
660 generation or reading. For example, you can generate mtree output which
661 only contains type, time, and uid keywords:
662 bsdtar -cf file.tar --format=mtree --options='!all,type,time,uid'
663 dir
664 or you can set the compression level used by gzip or xz compression:
665 bsdtar -czf file.tar --options='compression-level=9'.
666 For more details, see the explanation of the archive_read_set_options()
667 and archive_write_set_options() API calls that are described in
668 archive_read(3) and archive_write(3).
669
671 The bundled-arguments format is supported for compatibility with historic
672 implementations. It consists of an initial word (with no leading - char‐
673 acter) in which each character indicates an option. Arguments follow as
674 separate words. The order of the arguments must match the order of the
675 corresponding characters in the bundled command word. For example,
676 bsdtar tbf 32 file.tar
677 specifies three flags t, b, and f. The b and f flags both require argu‐
678 ments, so there must be two additional items on the command line. The 32
679 is the argument to the b flag, and file.tar is the argument to the f
680 flag.
681
682 The mode options c, r, t, u, and x and the options b, f, l, m, o, v, and
683 w comply with SUSv2.
684
685 For maximum portability, scripts that invoke tar should use the bundled-
686 argument format above, should limit themselves to the c, t, and x modes,
687 and the b, f, m, v, and w options.
688
689 Additional long options are provided to improve compatibility with other
690 tar implementations.
691
693 Certain security issues are common to many archiving programs, including
694 bsdtar. In particular, carefully-crafted archives can request that
695 bsdtar extract files to locations outside of the target directory. This
696 can potentially be used to cause unwitting users to overwrite files they
697 did not intend to overwrite. If the archive is being extracted by the
698 superuser, any file on the system can potentially be overwritten. There
699 are three ways this can happen. Although bsdtar has mechanisms to pro‐
700 tect against each one, savvy users should be aware of the implications:
701
702 · Archive entries can have absolute pathnames. By default, bsdtar
703 removes the leading / character from filenames before restoring
704 them to guard against this problem.
705
706 · Archive entries can have pathnames that include .. components.
707 By default, bsdtar will not extract files containing .. compo‐
708 nents in their pathname.
709
710 · Archive entries can exploit symbolic links to restore files to
711 other directories. An archive can restore a symbolic link to
712 another directory, then use that link to restore a file into that
713 directory. To guard against this, bsdtar checks each extracted
714 path for symlinks. If the final path element is a symlink, it
715 will be removed and replaced with the archive entry. If -U is
716 specified, any intermediate symlink will also be unconditionally
717 removed. If neither -U nor -P is specified, bsdtar will refuse
718 to extract the entry.
719 To protect yourself, you should be wary of any archives that come from
720 untrusted sources. You should examine the contents of an archive with
721 bsdtar -tf filename
722 before extraction. You should use the -k option to ensure that bsdtar
723 will not overwrite any existing files or the -U option to remove any pre-
724 existing files. You should generally not extract archives while running
725 with super-user privileges. Note that the -P option to bsdtar disables
726 the security checks above and allows you to extract an archive while pre‐
727 serving any absolute pathnames, .. components, or symlinks to other
728 directories.
729
731 bzip2(1), compress(1), cpio(1), gzip(1), mt(1), pax(1), shar(1), xz(1),
732 libarchive(3), libarchive-formats(5), tar(5)
733
735 There is no current POSIX standard for the tar command; it appeared in
736 ISO/IEC 9945-1:1996 (“POSIX.1”) but was dropped from IEEE Std 1003.1-2001
737 (“POSIX.1”). The options supported by this implementation were developed
738 by surveying a number of existing tar implementations as well as the old
739 POSIX specification for tar and the current POSIX specification for pax.
740
741 The ustar and pax interchange file formats are defined by IEEE Std
742 1003.1-2001 (“POSIX.1”) for the pax command.
743
745 A tar command appeared in Seventh Edition Unix, which was released in
746 January, 1979. There have been numerous other implementations, many of
747 which extended the file format. John Gilmore's pdtar public-domain
748 implementation (circa November, 1987) was quite influential, and formed
749 the basis of GNU tar. GNU tar was included as the standard system tar in
750 FreeBSD beginning with FreeBSD 1.0.
751
752 This is a complete re-implementation based on the libarchive(3) library.
753 It was first released with FreeBSD 5.4 in May, 2005.
754
756 This program follows ISO/IEC 9945-1:1996 (“POSIX.1”) for the definition
757 of the -l option. Note that GNU tar prior to version 1.15 treated -l as
758 a synonym for the --one-file-system option.
759
760 The -C dir option may differ from historic implementations.
761
762 All archive output is written in correctly-sized blocks, even if the out‐
763 put is being compressed. Whether or not the last output block is padded
764 to a full block size varies depending on the format and the output
765 device. For tar and cpio formats, the last block of output is padded to
766 a full block size if the output is being written to standard output or to
767 a character or block device such as a tape drive. If the output is being
768 written to a regular file, the last block will not be padded. Many com‐
769 pressors, including gzip(1) and bzip2(1), complain about the null padding
770 when decompressing an archive created by bsdtar, although they still
771 extract it correctly.
772
773 The compression and decompression is implemented internally, so there may
774 be insignificant differences between the compressed output generated by
775 bsdtar -czf - file
776 and that generated by
777 bsdtar -cf - file | gzip
778
779 The default should be to read and write archives to the standard I/O
780 paths, but tradition (and POSIX) dictates otherwise.
781
782 The r and u modes require that the archive be uncompressed and located in
783 a regular file on disk. Other archives can be modified using c mode with
784 the @archive-file extension.
785
786 To archive a file called @foo or -foo you must specify it as ./@foo or
787 ./-foo, respectively.
788
789 In create mode, a leading ./ is always removed. A leading / is stripped
790 unless the -P option is specified.
791
792 There needs to be better support for file selection on both create and
793 extract.
794
795 There is not yet any support for multi-volume archives.
796
797 Converting between dissimilar archive formats (such as tar and cpio)
798 using the @- convention can cause hard link information to be lost.
799 (This is a consequence of the incompatible ways that different archive
800 formats store hardlink information.)
801
802BSD February 25, 2017 BSD