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 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 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 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 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 @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 -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 --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 -B, --read-full-blocks
94 Ignored for compatibility with other tar(1) implementations.
95 -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 -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 --chroot
108 (x mode only) chroot() to the current directory after processing
109 any -C options and before extracting any files.
110 --clear-nochange-fflags
112 (x mode only) Before removing file system objects to replace
113 them, clear platform-specific file attributes or file flags that
114 might prevent removal.
115 --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 --exclude-vcs
122 Do not process files or directories internally used by the ver‐
123 sion control systems ‘CVS’, ‘RCS’, ‘SCCS’, ‘SVN’, ‘Arch’,
124 ‘Bazaar’, ‘Mercurial’ and ‘Darcs’.
125 --fflags
127 (c, r, u, x modes only) Archive or extract platform-specific file
128 attributes or file flags. This is the reverse of --no-fflags and
129 the default behavior in c, r, and u modes or if bsdtar is run in
130 x mode as root.
131 --format format
133 (c, r, u mode only) Use the specified format for the created ar‐
134 chive. Supported formats include “cpio”, “pax”, “shar”, and
135 “ustar”. Other formats may also be supported; see
136 libarchive-formats(5) for more information about currently-sup‐
137 ported formats. In r and u modes, when extending an existing ar‐
138 chive, the format specified here must be compatible with the for‐
139 mat of the existing archive on disk.
140 -f file, --file file
142 Read the archive from or write the archive to the specified file.
143 The filename can be - for standard input or standard output. The
144 default varies by system; on FreeBSD, the default is /dev/sa0; on
145 Linux, the default is /dev/st0.
146 --gid id
148 Use the provided group id number. On extract, this overrides the
149 group id in the archive; the group name in the archive will be
150 ignored. On create, this overrides the group id read from disk;
151 if --gname is not also specified, the group name will be set to
152 match the group id.
153 --gname name
155 Use the provided group name. On extract, this overrides the
156 group name in the archive; if the provided group name does not
157 exist on the system, the group id (from the archive or from the
158 --gid option) will be used instead. On create, this sets the
159 group name that will be stored in the archive; the name will not
160 be verified against the system group database.
161 -H (c and r modes only) Symbolic links named on the command line
163 will be followed; the target of the link will be archived, not
164 the link itself.
165 -h (c and r modes only) Synonym for -L.
167 -I Synonym for -T.
169 --help Show usage.
171 --hfsCompression
173 (x mode only) Mac OS X specific (v10.6 or later). Compress
174 extracted regular files with HFS+ compression.
175 --ignore-zeros
177 An alias of --options read_concatenated_archives for compatibil‐
178 ity with GNU tar.
179 --include pattern
181 Process only files or directories that match the specified pat‐
182 tern. Note that exclusions specified with --exclude take prece‐
183 dence over inclusions. If no inclusions are explicitly speci‐
184 fied, all entries are processed by default. The --include option
185 is especially useful when filtering archives. For example, the
186 command
187 bsdtar -c -f new.tar --include='*foo*' @old.tgz
188 creates a new archive new.tar containing only the entries from
189 old.tgz containing the string ‘foo’.
190 -J, --xz
192 (c mode only) Compress the resulting archive with xz(1). In
193 extract or list modes, this option is ignored. Note that this
194 tar implementation recognizes XZ compression automatically when
195 reading archives.
196 -j, --bzip, --bzip2, --bunzip2
198 (c mode only) Compress the resulting archive with bzip2(1). In
199 extract or list modes, this option is ignored. Note that this
200 tar implementation recognizes bzip2 compression automatically
201 when reading archives.
202 -k, --keep-old-files
204 (x mode only) Do not overwrite existing files. In particular, if
205 a file appears more than once in an archive, later copies will
206 not overwrite earlier copies.
207 --keep-newer-files
209 (x mode only) Do not overwrite existing files that are newer than
210 the versions appearing in the archive being extracted.
211 -L, --dereference
213 (c and r modes only) All symbolic links will be followed. Nor‐
214 mally, symbolic links are archived as such. With this option,
215 the target of the link will be archived instead.
216 -l, --check-links
218 (c and r modes only) Issue a warning message unless all links to
219 each file are archived.
220 --lrzip
222 (c mode only) Compress the resulting archive with lrzip(1). In
223 extract or list modes, this option is ignored. Note that this
224 tar implementation recognizes lrzip compression automatically
225 when reading archives.
226 --lz4 (c mode only) Compress the archive with lz4-compatible compres‐
228 sion before writing it. In extract or list modes, this option is
229 ignored. Note that this tar implementation recognizes lz4 com‐
230 pression automatically when reading archives.
231 --zstd (c mode only) Compress the archive with zstd-compatible compres‐
233 sion before writing it. In extract or list modes, this option is
234 ignored. Note that this tar implementation recognizes zstd com‐
235 pression automatically when reading archives.
236 --lzma (c mode only) Compress the resulting archive with the original
238 LZMA algorithm. In extract or list modes, this option is
239 ignored. Use of this option is discouraged and new archives
240 should be created with --xz instead. Note that this tar imple‐
241 mentation recognizes LZMA compression automatically when reading
242 archives.
243 --lzop (c mode only) Compress the resulting archive with lzop(1). In
245 extract or list modes, this option is ignored. Note that this
246 tar implementation recognizes LZO compression automatically when
247 reading archives.
248 -m, --modification-time
250 (x mode only) Do not extract modification time. By default, the
251 modification time is set to the time stored in the archive.
252 --mac-metadata
254 (c, r, u and x mode only) Mac OS X specific. Archive or extract
255 extended ACLs and extended file attributes using copyfile(3) in
256 AppleDouble format. This is the reverse of --no-mac-metadata.
257 and the default behavior in c, r, and u modes or if bsdtar is run
258 in x mode as root.
259 -n, --norecurse, --no-recursion
261 Do not operate recursively on the content of directories.
262 --newer date
264 (c, r, u modes only) Only include files and directories newer
265 than the specified date. This compares ctime entries.
266 --newer-mtime date
268 (c, r, u modes only) Like --newer, except it compares mtime
269 entries instead of ctime entries.
270 --newer-than file
272 (c, r, u modes only) Only include files and directories newer
273 than the specified file. This compares ctime entries.
274 --newer-mtime-than file
276 (c, r, u modes only) Like --newer-than, except it compares mtime
277 entries instead of ctime entries.
278 --nodump
280 (c and r modes only) Honor the nodump file flag by skipping this
281 file.
282 --nopreserveHFSCompression
284 (x mode only) Mac OS X specific (v10.6 or later). Do not compress
285 extracted regular files which were compressed with HFS+ compres‐
286 sion before archived. By default, compress the regular files
287 again with HFS+ compression.
288 --null (use with -I or -T) Filenames or patterns are separated by null
290 characters, not by newlines. This is often used to read file‐
291 names output by the -print0 option to find(1).
292 --no-acls
294 (c, r, u, x modes only) Do not archive or extract POSIX.1e or
295 NFSv4 ACLs. This is the reverse of --acls and the default behav‐
296 ior if bsdtar is run as non-root in x mode (on Mac OS X as any
297 user in c, r, u and x modes).
298 --no-fflags
300 (c, r, u, x modes only) Do not archive or extract file attributes
301 or file flags. This is the reverse of --fflags and the default
302 behavior if bsdtar is run as non-root in x mode.
303 --no-mac-metadata
305 (x mode only) Mac OS X specific. Do not archive or extract ACLs
306 and extended file attributes using copyfile(3) in AppleDouble
307 format. This is the reverse of --mac-metadata. and the default
308 behavior if bsdtar is run as non-root in x mode.
309 --no-same-owner
311 (x mode only) Do not extract owner and group IDs. This is the
312 reverse of --same-owner and the default behavior if bsdtar is run
313 as non-root.
314 --no-same-permissions
316 (x mode only) Do not extract full permissions (SGID, SUID, sticky
317 bit, file attributes or file flags, extended file attributes and
318 ACLs). This is the reverse of -p and the default behavior if
319 bsdtar is run as non-root.
320 --no-xattrs
322 (c, r, u, x modes only) Do not archive or extract extended file
323 attributes. This is the reverse of --xattrs and the default
324 behavior if bsdtar is run as non-root in x mode.
325 --numeric-owner
327 This is equivalent to --uname "" --gname "". On extract, it
328 causes user and group names in the archive to be ignored in favor
329 of the numeric user and group ids. On create, it causes user and
330 group names to not be stored in the archive.
331 -O, --to-stdout
333 (x, t modes only) In extract (-x) mode, files will be written to
334 standard out rather than being extracted to disk. In list (-t)
335 mode, the file listing will be written to stderr rather than the
336 usual stdout.
337 -o (x mode) Use the user and group of the user running the program
339 rather than those specified in the archive. Note that this has
340 no significance unless -p is specified, and the program is being
341 run by the root user. In this case, the file modes and flags
342 from the archive will be restored, but ACLs or owner information
343 in the archive will be discarded.
344 -o (c, r, u mode) A synonym for --format ustar
346 --older date
348 (c, r, u modes only) Only include files and directories older
349 than the specified date. This compares ctime entries.
350 --older-mtime date
352 (c, r, u modes only) Like --older, except it compares mtime
353 entries instead of ctime entries.
354 --older-than file
356 (c, r, u modes only) Only include files and directories older
357 than the specified file. This compares ctime entries.
358 --older-mtime-than file
360 (c, r, u modes only) Like --older-than, except it compares mtime
361 entries instead of ctime entries.
362 --one-file-system
364 (c, r, and u modes) Do not cross mount points.
365 --options options
367 Select optional behaviors for particular modules. The argument
368 is a text string containing comma-separated keywords and values.
369 These are passed to the modules that handle particular formats to
370 control how those formats will behave. Each option has one of
371 the following forms:
372 key=value
373 The key will be set to the specified value in every mod‐
374 ule that supports it. Modules that do not support this
375 key will ignore it.
376 key The key will be enabled in every module that supports it.
377 This is equivalent to key=1.
378 !key The key will be disabled in every module that supports
379 it.
380 module:key=value, module:key, module:!key
381 As above, but the corresponding key and value will be
382 provided only to modules whose name matches module.
383 The currently supported modules and keys are:
384 iso9660:joliet
385 Support Joliet extensions. This is enabled by default,
386 use !joliet or iso9660:!joliet to disable.
387 iso9660:rockridge
388 Support Rock Ridge extensions. This is enabled by
389 default, use !rockridge or iso9660:!rockridge to disable.
390 gzip:compression-level
391 A decimal integer from 1 to 9 specifying the gzip com‐
392 pression level.
393 gzip:timestamp
394 Store timestamp. This is enabled by default, use
395 !timestamp or gzip:!timestamp to disable.
396 lrzip:compression=type
397 Use type as compression method. Supported values are
398 bzip2, gzip, lzo (ultra fast), and zpaq (best, extremely
399 slow).
400 lrzip:compression-level
401 A decimal integer from 1 to 9 specifying the lrzip com‐
402 pression level.
403 lz4:compression-level
404 A decimal integer from 1 to 9 specifying the lzop com‐
405 pression level.
406 lz4:stream-checksum
407 Enable stream checksum. This is by default, use
408 lz4:!stream-checksum to disable.
409 lz4:block-checksum
410 Enable block checksum (Disabled by default).
411 lz4:block-size
412 A decimal integer from 4 to 7 specifying the lz4 compres‐
413 sion block size (7 is set by default).
414 lz4:block-dependence
415 Use the previous block of the block being compressed for
416 a compression dictionary to improve compression ratio.
417 zstd:compression-level
418 A decimal integer from 1 to 22 specifying the zstd com‐
419 pression level.
420 lzop:compression-level
421 A decimal integer from 1 to 9 specifying the lzop com‐
422 pression level.
423 xz:compression-level
424 A decimal integer from 0 to 9 specifying the xz compres‐
425 sion level.
426 mtree:keyword
427 The mtree writer module allows you to specify which mtree
428 keywords will be included in the output. Supported key‐
429 words include: cksum, device, flags, gid, gname, indent,
430 link, md5, mode, nlink, rmd160, sha1, sha256, sha384,
431 sha512, size, time, uid, uname. The default is equiva‐
432 lent to: “device, flags, gid, gname, link, mode, nlink,
433 size, time, type, uid, uname”.
434 mtree:all
435 Enables all of the above keywords. You can also use
436 mtree:!all to disable all keywords.
437 mtree:use-set
438 Enable generation of /set lines in the output.
439 mtree:indent
440 Produce human-readable output by indenting options and
441 splitting lines to fit into 80 columns.
442 zip:compression=type
443 Use type as compression method. Supported values are
444 store (uncompressed) and deflate (gzip algorithm).
445 zip:encryption
446 Enable encryption using traditional zip encryption.
447 zip:encryption=type
448 Use type as encryption type. Supported values are
449 zipcrypt (traditional zip encryption), aes128 (WinZip
450 AES-128 encryption) and aes256 (WinZip AES-256 encryp‐
451 tion).
452 read_concatenated_archives
453 Ignore zeroed blocks in the archive, which occurs when
454 multiple tar archives have been concatenated together.
455 Without this option, only the contents of the first con‐
456 catenated archive would be read. This option is compara‐
457 ble to the -i, --ignore-zeros option of GNU tar.
458 If a provided option is not supported by any module, that is a
459 fatal error.
460 -P, --absolute-paths
462 Preserve pathnames. By default, absolute pathnames (those that
463 begin with a / character) have the leading slash removed both
464 when creating archives and extracting from them. Also, bsdtar
465 will refuse to extract archive entries whose pathnames contain ..
466 or whose target directory would be altered by a symlink. This
467 option suppresses these behaviors.
468 -p, --insecure, --preserve-permissions
470 (x mode only) Preserve file permissions. Attempt to restore the
471 full permissions, including file modes, file attributes or file
472 flags, extended file attributes and ACLs, if available, for each
473 item extracted from the archive. This is the reverse of
474 --no-same-permissions and the default if bsdtar is being run as
475 root. It can be partially overridden by also specifying
476 --no-acls, --no-fflags, --no-mac-metadata or --no-xattrs.
477 --passphrase passphrase
479 The passphrase is used to extract or create an encrypted archive.
480 Currently, zip is the only supported format that supports encryp‐
481 tion. You shouldn't use this option unless you realize how inse‐
482 cure use of this option is.
483 --posix
485 (c, r, u mode only) Synonym for --format pax
486 -q, --fast-read
488 (x and t mode only) Extract or list only the first archive entry
489 that matches each pattern or filename operand. Exit as soon as
490 each specified pattern or filename has been matched. By default,
491 the archive is always read to the very end, since there can be
492 multiple entries with the same name and, by convention, later
493 entries overwrite earlier entries. This option is provided as a
494 performance optimization.
495 -S (x mode only) Extract files as sparse files. For every block on
497 disk, check first if it contains only NULL bytes and seek over it
498 otherwise. This works similar to the conv=sparse option of dd.
499 -s pattern
501 Modify file or archive member names according to pattern. The
502 pattern has the format /old/new/[ghHprRsS] where old is a basic
503 regular expression, new is the replacement string of the matched
504 part, and the optional trailing letters modify how the replace‐
505 ment is handled. If old is not matched, the pattern is skipped.
506 Within new, ~ is substituted with the match, \1 to \9 with the
507 content of the corresponding captured group. The optional trail‐
508 ing g specifies that matching should continue after the matched
509 part and stop on the first unmatched pattern. The optional
510 trailing s specifies that the pattern applies to the value of
511 symbolic links. The optional trailing p specifies that after a
512 successful substitution the original path name and the new path
513 name should be printed to standard error. Optional trailing H,
514 R, or S characters suppress substitutions for hardlink targets,
515 regular filenames, or symlink targets, respectively. Optional
516 trailing h, r, or s characters enable substitutions for hardlink
517 targets, regular filenames, or symlink targets, respectively.
518 The default is hrs which applies substitutions to all names. In
519 particular, it is never necessary to specify h, r, or s.
520 --same-owner
522 (x mode only) Extract owner and group IDs. This is the reverse
523 of --no-same-owner and the default behavior if bsdtar is run as
524 root.
525 --strip-components count
527 Remove the specified number of leading path elements. Pathnames
528 with fewer elements will be silently skipped. Note that the
529 pathname is edited after checking inclusion/exclusion patterns
530 but before security checks.
531 -T filename, --files-from filename
533 In x or t mode, bsdtar will read the list of names to be
534 extracted from filename. In c mode, bsdtar will read names to be
535 archived from filename. The special name “-C” on a line by
536 itself will cause the current directory to be changed to the
537 directory specified on the following line. Names are terminated
538 by newlines unless --null is specified. Note that --null also
539 disables the special handling of lines containing “-C”. Note:
540 If you are generating lists of files using find(1), you probably
541 want to use -n as well.
542 --totals
544 (c, r, u modes only) After archiving all files, print a summary
545 to stderr.
546 -U, --unlink, --unlink-first
548 (x mode only) Unlink files before creating them. This can be a
549 minor performance optimization if most files already exist, but
550 can make things slower if most files do not already exist. This
551 flag also causes bsdtar to remove intervening directory symlinks
552 instead of reporting an error. See the SECURITY section below
553 for more details.
554 --uid id
556 Use the provided user id number and ignore the user name from the
557 archive. On create, if --uname is not also specified, the user
558 name will be set to match the user id.
559 --uname name
561 Use the provided user name. On extract, this overrides the user
562 name in the archive; if the provided user name does not exist on
563 the system, it will be ignored and the user id (from the archive
564 or from the --uid option) will be used instead. On create, this
565 sets the user name that will be stored in the archive; the name
566 is not verified against the system user database.
567 --use-compress-program program
569 Pipe the input (in x or t mode) or the output (in c mode) through
570 program instead of using the builtin compression support.
571 -v, --verbose
573 Produce verbose output. In create and extract modes, bsdtar will
574 list each file name as it is read from or written to the archive.
575 In list mode, bsdtar will produce output similar to that of
576 ls(1). An additional -v option will also provide ls-like details
577 in create and extract mode.
578 --version
580 Print version of bsdtar and libarchive, and exit.
581 -w, --confirmation, --interactive
583 Ask for confirmation for every action.
584 -X filename, --exclude-from filename
586 Read a list of exclusion patterns from the specified file. See
587 --exclude for more information about the handling of exclusions.
588 --xattrs
590 (c, r, u, x modes only) Archive or extract extended file
591 attributes. This is the reverse of --no-xattrs and the default
592 behavior in c, r, and u modes or if bsdtar is run in x mode as
593 root.
594 -y (c mode only) Compress the resulting archive with bzip2(1). In
596 extract or list modes, this option is ignored. Note that this
597 tar implementation recognizes bzip2 compression automatically
598 when reading archives.
599 -Z, --compress, --uncompress
601 (c mode only) Compress the resulting archive with compress(1).
602 In extract or list modes, this option is ignored. Note that this
603 tar implementation recognizes compress compression automatically
604 when reading archives.
605 -z, --gunzip, --gzip
607 (c mode only) Compress the resulting archive with gzip(1). In
608 extract or list modes, this option is ignored. Note that this
609 tar implementation recognizes gzip compression automatically when
610 reading archives.
611
613 The following environment variables affect the execution of bsdtar:
614 TAR_READER_OPTIONS
616 The default options for format readers and compression read‐
617 ers. The --options option overrides this.
618 TAR_WRITER_OPTIONS
620 The default options for format writers and compression writ‐
621 ers. The --options option overrides this.
622 LANG The locale to use. See environ(7) for more information.
624 TAPE The default device. The -f option overrides this. Please see
626 the description of the -f option above for more details.
627 TZ The timezone to use when displaying dates. See environ(7) for
629 more information.
630
632 The bsdtar utility exits 0 on success, and >0 if an error occurs.
633
635 The following creates a new archive called file.tar.gz that contains two
636 files source.c and source.h:
637 bsdtar -czf file.tar.gz source.c source.h
638 To view a detailed table of contents for this archive:
640 bsdtar -tvf file.tar.gz
641 To extract all entries from the archive on the default tape drive:
643 bsdtar -x
644 To examine the contents of an ISO 9660 cdrom image:
646 bsdtar -tf image.iso
647 To move file hierarchies, invoke bsdtar as
649 bsdtar -cf - -C srcdir . | bsdtar -xpf - -C destdir
650 or more traditionally
651 cd srcdir ; bsdtar -cf - . | (cd destdir ; bsdtar -xpf -)
652 In create mode, the list of files and directories to be archived can also
654 include directory change instructions of the form -Cfoo/baz and archive
655 inclusions of the form @archive-file. For example, the command line
656 bsdtar -c -f new.tar foo1 @old.tgz -C/tmp foo2
657 will create a new archive new.tar. bsdtar will read the file foo1 from
658 the current directory and add it to the output archive. It will then
659 read each entry from old.tgz and add those entries to the output archive.
660 Finally, it will switch to the /tmp directory and add foo2 to the output
661 archive.
662 An input file in mtree(5) format can be used to create an output archive
664 with arbitrary ownership, permissions, or names that differ from existing
665 data on disk:
666 $ cat input.mtree
668 #mtree
669 usr/bin uid=0 gid=0 mode=0755 type=dir
670 usr/bin/ls uid=0 gid=0 mode=0755 type=file content=myls
671 $ tar -cvf output.tar @input.mtree
672 The --newer and --newer-mtime switches accept a variety of common date
674 and time specifications, including “12 Mar 2005 7:14:29pm”, “2005-03-12
675 19:14”, “5 minutes ago”, and “19:14 PST May 1”.
676 The --options argument can be used to control various details of archive
678 generation or reading. For example, you can generate mtree output which
679 only contains type, time, and uid keywords:
680 bsdtar -cf file.tar --format=mtree --options='!all,type,time,uid'
681 dir
682 or you can set the compression level used by gzip or xz compression:
683 bsdtar -czf file.tar --options='compression-level=9'.
684 For more details, see the explanation of the archive_read_set_options()
685 and archive_write_set_options() API calls that are described in
686 archive_read(3) and archive_write(3).
687
689 The bundled-arguments format is supported for compatibility with historic
690 implementations. It consists of an initial word (with no leading - char‐
691 acter) in which each character indicates an option. Arguments follow as
692 separate words. The order of the arguments must match the order of the
693 corresponding characters in the bundled command word. For example,
694 bsdtar tbf 32 file.tar
695 specifies three flags t, b, and f. The b and f flags both require argu‐
696 ments, so there must be two additional items on the command line. The 32
697 is the argument to the b flag, and file.tar is the argument to the f
698 flag.
699 The mode options c, r, t, u, and x and the options b, f, l, m, o, v, and
701 w comply with SUSv2.
702 For maximum portability, scripts that invoke tar should use the bundled-
704 argument format above, should limit themselves to the c, t, and x modes,
705 and the b, f, m, v, and w options.
706 Additional long options are provided to improve compatibility with other
708 tar implementations.
709
711 Certain security issues are common to many archiving programs, including
712 bsdtar. In particular, carefully-crafted archives can request that
713 bsdtar extract files to locations outside of the target directory. This
714 can potentially be used to cause unwitting users to overwrite files they
715 did not intend to overwrite. If the archive is being extracted by the
716 superuser, any file on the system can potentially be overwritten. There
717 are three ways this can happen. Although bsdtar has mechanisms to pro‐
718 tect against each one, savvy users should be aware of the implications:
719 · Archive entries can have absolute pathnames. By default, bsdtar
721 removes the leading / character from filenames before restoring
722 them to guard against this problem.
723 · Archive entries can have pathnames that include .. components.
725 By default, bsdtar will not extract files containing .. compo‐
726 nents in their pathname.
727 · Archive entries can exploit symbolic links to restore files to
729 other directories. An archive can restore a symbolic link to
730 another directory, then use that link to restore a file into that
731 directory. To guard against this, bsdtar checks each extracted
732 path for symlinks. If the final path element is a symlink, it
733 will be removed and replaced with the archive entry. If -U is
734 specified, any intermediate symlink will also be unconditionally
735 removed. If neither -U nor -P is specified, bsdtar will refuse
736 to extract the entry.
737 To protect yourself, you should be wary of any archives that come from
738 untrusted sources. You should examine the contents of an archive with
739 bsdtar -tf filename
740 before extraction. You should use the -k option to ensure that bsdtar
741 will not overwrite any existing files or the -U option to remove any pre-
742 existing files. You should generally not extract archives while running
743 with super-user privileges. Note that the -P option to bsdtar disables
744 the security checks above and allows you to extract an archive while pre‐
745 serving any absolute pathnames, .. components, or symlinks to other
746 directories.
747
749 bzip2(1), compress(1), cpio(1), gzip(1), mt(1), pax(1), shar(1), xz(1),
750 libarchive(3), libarchive-formats(5), tar(5)
751
753 There is no current POSIX standard for the tar command; it appeared in
754 ISO/IEC 9945-1:1996 (“POSIX.1”) but was dropped from IEEE Std 1003.1-2001
755 (“POSIX.1”). The options supported by this implementation were developed
756 by surveying a number of existing tar implementations as well as the old
757 POSIX specification for tar and the current POSIX specification for pax.
758 The ustar and pax interchange file formats are defined by IEEE Std
760 1003.1-2001 (“POSIX.1”) for the pax command.
761
763 A tar command appeared in Seventh Edition Unix, which was released in
764 January, 1979. There have been numerous other implementations, many of
765 which extended the file format. John Gilmore's pdtar public-domain
766 implementation (circa November, 1987) was quite influential, and formed
767 the basis of GNU tar. GNU tar was included as the standard system tar in
768 FreeBSD beginning with FreeBSD 1.0.
769 This is a complete re-implementation based on the libarchive(3) library.
771 It was first released with FreeBSD 5.4 in May, 2005.
772
774 This program follows ISO/IEC 9945-1:1996 (“POSIX.1”) for the definition
775 of the -l option. Note that GNU tar prior to version 1.15 treated -l as
776 a synonym for the --one-file-system option.
777 The -C dir option may differ from historic implementations.
779 All archive output is written in correctly-sized blocks, even if the out‐
781 put is being compressed. Whether or not the last output block is padded
782 to a full block size varies depending on the format and the output
783 device. For tar and cpio formats, the last block of output is padded to
784 a full block size if the output is being written to standard output or to
785 a character or block device such as a tape drive. If the output is being
786 written to a regular file, the last block will not be padded. Many com‐
787 pressors, including gzip(1) and bzip2(1), complain about the null padding
788 when decompressing an archive created by bsdtar, although they still
789 extract it correctly.
790 The compression and decompression is implemented internally, so there may
792 be insignificant differences between the compressed output generated by
793 bsdtar -czf - file
794 and that generated by
795 bsdtar -cf - file | gzip
796 The default should be to read and write archives to the standard I/O
798 paths, but tradition (and POSIX) dictates otherwise.
799 The r and u modes require that the archive be uncompressed and located in
801 a regular file on disk. Other archives can be modified using c mode with
802 the @archive-file extension.
803 To archive a file called @foo or -foo you must specify it as ./@foo or
805 ./-foo, respectively.
806 In create mode, a leading ./ is always removed. A leading / is stripped
808 unless the -P option is specified.
809 There needs to be better support for file selection on both create and
811 extract.
812 There is not yet any support for multi-volume archives.
814 Converting between dissimilar archive formats (such as tar and cpio)
816 using the @- convention can cause hard link information to be lost.
817 (This is a consequence of the incompatible ways that different archive
818 formats store hardlink information.)
819BSD June 3, 2019 BSD