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 flags that might prevent
114 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 --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 --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 -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 --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 --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 -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 -h (c and r modes only) Synonym for -L.
161 -I Synonym for -T.
163 --help Show usage.
165 --hfsCompression
167 (x mode only) Mac OS X specific (v10.6 or later). Compress
168 extracted regular files with HFS+ compression.
169 --ignore-zeros
171 An alias of --options read_concatenated_archives for compatibil‐
172 ity with GNU tar.
173 --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 -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 this
188 tar implementation recognizes XZ compression automatically when
189 reading archives.
190 -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 this
194 tar implementation recognizes bzip2 compression automatically
195 when reading archives.
196 -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 --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 -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 -l, --check-links
212 (c and r modes only) Issue a warning message unless all links to
213 each file are archived.
214 --lrzip
216 (c mode only) Compress the resulting archive with lrzip(1). In
217 extract or list modes, this option is ignored. Note that this
218 tar implementation recognizes lrzip compression automatically
219 when reading archives.
220 --lz4 (c mode only) Compress the archive with lz4-compatible compres‐
222 sion before writing it. In extract or list modes, this option is
223 ignored. Note that this tar implementation recognizes lz4 com‐
224 pression automatically when reading archives.
225 --zstd (c mode only) Compress the archive with zstd-compatible compres‐
227 sion before writing it. In extract or list modes, this option is
228 ignored. Note that this tar implementation recognizes zstd com‐
229 pression automatically when reading archives.
230 --lzma (c mode only) Compress the resulting archive with the original
232 LZMA algorithm. In extract or list modes, this option is
233 ignored. Use of this option is discouraged and new archives
234 should be created with --xz instead. Note that this tar imple‐
235 mentation recognizes LZMA compression automatically when reading
236 archives.
237 --lzop (c mode only) Compress the resulting archive with lzop(1). In
239 extract or list modes, this option is ignored. Note that this
240 tar implementation recognizes LZO compression automatically when
241 reading archives.
242 -m, --modification-time
244 (x mode only) Do not extract modification time. By default, the
245 modification time is set to the time stored in the archive.
246 --mac-metadata
248 (c, r, u and x mode only) Mac OS X specific. Archive or extract
249 extended ACLs and extended attributes using copyfile(3) in Apple‐
250 Double format. This is the reverse of --no-mac-metadata. and the
251 default behavior in c, r, and u modes or if bsdtar is run in x
252 mode as root.
253 -n, --norecurse, --no-recursion
255 (c, r, u modes only) Do not recursively archive the contents of
256 directories.
257 --newer date
259 (c, r, u modes only) Only include files and directories newer
260 than the specified date. This compares ctime entries.
261 --newer-mtime date
263 (c, r, u modes only) Like --newer, except it compares mtime
264 entries instead of ctime entries.
265 --newer-than file
267 (c, r, u modes only) Only include files and directories newer
268 than the specified file. This compares ctime entries.
269 --newer-mtime-than file
271 (c, r, u modes only) Like --newer-than, except it compares mtime
272 entries instead of ctime entries.
273 --nodump
275 (c and r modes only) Honor the nodump file flag by skipping this
276 file.
277 --nopreserveHFSCompression
279 (x mode only) Mac OS X specific (v10.6 or later). Do not compress
280 extracted regular files which were compressed with HFS+ compres‐
281 sion before archived. By default, compress the regular files
282 again with HFS+ compression.
283 --null (use with -I or -T) Filenames or patterns are separated by null
285 characters, not by newlines. This is often used to read file‐
286 names output by the -print0 option to find(1).
287 --no-acls
289 (c, r, u, x modes only) Do not archive or extract POSIX.1e or
290 NFSv4 ACLs. This is the reverse of --acls and the default behav‐
291 ior if bsdtar is run as non-root in x mode (on Mac OS X as any
292 user in c, r, u and x modes).
293 --no-fflags
295 (c, r, u, x modes only) Do not archive or extract file flags.
296 This is the reverse of --fflags and the default behavior if
297 bsdtar is run as non-root in x mode.
298 --no-mac-metadata
300 (x mode only) Mac OS X specific. Do not archive or extract ACLs
301 and extended attributes using copyfile(3) in AppleDouble format.
302 This is the reverse of --mac-metadata. and the default behavior
303 if bsdtar is run as non-root in x mode.
304 -n, --norecurse, --no-recursion
306 --no-same-owner
308 (x mode only) Do not extract owner and group IDs. This is the
309 reverse of --same-owner and the default behavior if bsdtar is run
310 as non-root.
311 --no-same-permissions
313 (x mode only) Do not extract full permissions (SGID, SUID, sticky
314 bit, ACLs, extended attributes or extended file flags). This is
315 the reverse of -p and the default behavior if bsdtar is run as
316 non-root.
317 --no-xattrs
319 (c, r, u, x modes only) Do not archive or extract extended
320 attributes. This is the reverse of --xattrs and the default
321 behavior if bsdtar is run as non-root in x mode.
322 --numeric-owner
324 This is equivalent to --uname "" --gname "". On extract, it
325 causes user and group names in the archive to be ignored in favor
326 of the numeric user and group ids. On create, it causes user and
327 group names to not be stored in the archive.
328 -O, --to-stdout
330 (x, t modes only) In extract (-x) mode, files will be written to
331 standard out rather than being extracted to disk. In list (-t)
332 mode, the file listing will be written to stderr rather than the
333 usual stdout.
334 -o (x mode) Use the user and group of the user running the program
336 rather than those specified in the archive. Note that this has
337 no significance unless -p is specified, and the program is being
338 run by the root user. In this case, the file modes and flags
339 from the archive will be restored, but ACLs or owner information
340 in the archive will be discarded.
341 -o (c, r, u mode) A synonym for --format ustar
343 --older date
345 (c, r, u modes only) Only include files and directories older
346 than the specified date. This compares ctime entries.
347 --older-mtime date
349 (c, r, u modes only) Like --older, except it compares mtime
350 entries instead of ctime entries.
351 --older-than file
353 (c, r, u modes only) Only include files and directories older
354 than the specified file. This compares ctime entries.
355 --older-mtime-than file
357 (c, r, u modes only) Like --older-than, except it compares mtime
358 entries instead of ctime entries.
359 --one-file-system
361 (c, r, and u modes) Do not cross mount points.
362 --options options
364 Select optional behaviors for particular modules. The argument
365 is a text string containing comma-separated keywords and values.
366 These are passed to the modules that handle particular formats to
367 control how those formats will behave. Each option has one of
368 the following forms:
369 key=value
370 The key will be set to the specified value in every mod‐
371 ule that supports it. Modules that do not support this
372 key will ignore it.
373 key The key will be enabled in every module that supports it.
374 This is equivalent to key=1.
375 !key The key will be disabled in every module that supports
376 it.
377 module:key=value, module:key, module:!key
378 As above, but the corresponding key and value will be
379 provided only to modules whose name matches module.
380 The currently supported modules and keys are:
381 iso9660:joliet
382 Support Joliet extensions. This is enabled by default,
383 use !joliet or iso9660:!joliet to disable.
384 iso9660:rockridge
385 Support Rock Ridge extensions. This is enabled by
386 default, use !rockridge or iso9660:!rockridge to disable.
387 gzip:compression-level
388 A decimal integer from 1 to 9 specifying the gzip com‐
389 pression level.
390 gzip:timestamp
391 Store timestamp. This is enabled by default, use
392 !timestamp or gzip:!timestamp to disable.
393 lrzip:compression=type
394 Use type as compression method. Supported values are
395 bzip2, gzip, lzo (ultra fast), and zpaq (best, extremely
396 slow).
397 lrzip:compression-level
398 A decimal integer from 1 to 9 specifying the lrzip com‐
399 pression level.
400 lz4:compression-level
401 A decimal integer from 1 to 9 specifying the lzop com‐
402 pression level.
403 lz4:stream-checksum
404 Enable stream checksum. This is by default, use
405 lz4:!stream-checksum to disable.
406 lz4:block-checksum
407 Enable block checksum (Disabled by default).
408 lz4:block-size
409 A decimal integer from 4 to 7 specifying the lz4 compres‐
410 sion block size (7 is set by default).
411 lz4:block-dependence
412 Use the previous block of the block being compressed for
413 a compression dictionary to improve compression ratio.
414 zstd:compression-level
415 A decimal integer from 1 to 22 specifying the zstd com‐
416 pression level.
417 lzop:compression-level
418 A decimal integer from 1 to 9 specifying the lzop com‐
419 pression level.
420 xz:compression-level
421 A decimal integer from 0 to 9 specifying the xz compres‐
422 sion level.
423 mtree:keyword
424 The mtree writer module allows you to specify which mtree
425 keywords will be included in the output. Supported key‐
426 words include: cksum, device, flags, gid, gname, indent,
427 link, md5, mode, nlink, rmd160, sha1, sha256, sha384,
428 sha512, size, time, uid, uname. The default is equiva‐
429 lent to: “device, flags, gid, gname, link, mode, nlink,
430 size, time, type, uid, uname”.
431 mtree:all
432 Enables all of the above keywords. You can also use
433 mtree:!all to disable all keywords.
434 mtree:use-set
435 Enable generation of /set lines in the output.
436 mtree:indent
437 Produce human-readable output by indenting options and
438 splitting lines to fit into 80 columns.
439 zip:compression=type
440 Use type as compression method. Supported values are
441 store (uncompressed) and deflate (gzip algorithm).
442 zip:encryption
443 Enable encryption using traditional zip encryption.
444 zip:encryption=type
445 Use type as encryption type. Supported values are
446 zipcrypt (traditional zip encryption), aes128 (WinZip
447 AES-128 encryption) and aes256 (WinZip AES-256 encryp‐
448 tion).
449 read_concatenated_archives
450 Ignore zeroed blocks in the archive, which occurs when
451 multiple tar archives have been concatenated together.
452 Without this option, only the contents of the first con‐
453 catenated archive would be read. This option is compara‐
454 ble to the -i, --ignore-zeros option of GNU tar.
455 If a provided option is not supported by any module, that is a
456 fatal error.
457 -P, --absolute-paths
459 Preserve pathnames. By default, absolute pathnames (those that
460 begin with a / character) have the leading slash removed both
461 when creating archives and extracting from them. Also, bsdtar
462 will refuse to extract archive entries whose pathnames contain ..
463 or whose target directory would be altered by a symlink. This
464 option suppresses these behaviors.
465 -p, --insecure, --preserve-permissions
467 (x mode only) Preserve file permissions. Attempt to restore the
468 full permissions, including owner, file modes, ACLs, extended
469 attributes and extended file flags, if available, for each item
470 extracted from the archive. This is te reverse of
471 --no-same-permissions and the default if bsdtar is being run by
472 root and can be partially overridden by also specifying
473 --no-acls, --no-fflags, --no-mac-metadata or --no-xattrs.
474 --passphrase passphrase
476 The passphrase is used to extract or create an encrypted archive.
477 Currently, zip is the only supported format that supports encryp‐
478 tion. You shouldn't use this option unless you realize how inse‐
479 cure use of this option is.
480 --posix
482 (c, r, u mode only) Synonym for --format pax
483 -q, --fast-read
485 (x and t mode only) Extract or list only the first archive entry
486 that matches each pattern or filename operand. Exit as soon as
487 each specified pattern or filename has been matched. By default,
488 the archive is always read to the very end, since there can be
489 multiple entries with the same name and, by convention, later
490 entries overwrite earlier entries. This option is provided as a
491 performance optimization.
492 -S (x mode only) Extract files as sparse files. For every block on
494 disk, check first if it contains only NULL bytes and seek over it
495 otherwise. This works similar to the conv=sparse option of dd.
496 -s pattern
498 Modify file or archive member names according to pattern. The
499 pattern has the format /old/new/[ghHprRsS] where old is a basic
500 regular expression, new is the replacement string of the matched
501 part, and the optional trailing letters modify how the replace‐
502 ment is handled. If old is not matched, the pattern is skipped.
503 Within new, ~ is substituted with the match, \1 to \9 with the
504 content of the corresponding captured group. The optional trail‐
505 ing g specifies that matching should continue after the matched
506 part and stop on the first unmatched pattern. The optional
507 trailing s specifies that the pattern applies to the value of
508 symbolic links. The optional trailing p specifies that after a
509 successful substitution the original path name and the new path
510 name should be printed to standard error. Optional trailing H,
511 R, or S characters suppress substitutions for hardlink targets,
512 regular filenames, or symlink targets, respectively. Optional
513 trailing h, r, or s characters enable substitutions for hardlink
514 targets, regular filenames, or symlink targets, respectively.
515 The default is hrs which applies substitutions to all names. In
516 particular, it is never necessary to specify h, r, or s.
517 --same-owner
519 (x mode only) Extract owner and group IDs. This is the reverse
520 of --no-same-owner and the default behavior if bsdtar is run as
521 root.
522 --strip-components count
524 Remove the specified number of leading path elements. Pathnames
525 with fewer elements will be silently skipped. Note that the
526 pathname is edited after checking inclusion/exclusion patterns
527 but before security checks.
528 -T filename, --files-from filename
530 In x or t mode, bsdtar will read the list of names to be
531 extracted from filename. In c mode, bsdtar will read names to be
532 archived from filename. The special name “-C” on a line by
533 itself will cause the current directory to be changed to the
534 directory specified on the following line. Names are terminated
535 by newlines unless --null is specified. Note that --null also
536 disables the special handling of lines containing “-C”. Note:
537 If you are generating lists of files using find(1), you probably
538 want to use -n as well.
539 --totals
541 (c, r, u modes only) After archiving all files, print a summary
542 to stderr.
543 -U, --unlink, --unlink-first
545 (x mode only) Unlink files before creating them. This can be a
546 minor performance optimization if most files already exist, but
547 can make things slower if most files do not already exist. This
548 flag also causes bsdtar to remove intervening directory symlinks
549 instead of reporting an error. See the SECURITY section below
550 for more details.
551 --uid id
553 Use the provided user id number and ignore the user name from the
554 archive. On create, if --uname is not also specified, the user
555 name will be set to match the user id.
556 --uname name
558 Use the provided user name. On extract, this overrides the user
559 name in the archive; if the provided user name does not exist on
560 the system, it will be ignored and the user id (from the archive
561 or from the --uid option) will be used instead. On create, this
562 sets the user name that will be stored in the archive; the name
563 is not verified against the system user database.
564 --use-compress-program program
566 Pipe the input (in x or t mode) or the output (in c mode) through
567 program instead of using the builtin compression support.
568 -v, --verbose
570 Produce verbose output. In create and extract modes, bsdtar will
571 list each file name as it is read from or written to the archive.
572 In list mode, bsdtar will produce output similar to that of
573 ls(1). An additional -v option will also provide ls-like details
574 in create and extract mode.
575 --version
577 Print version of bsdtar and libarchive, and exit.
578 -w, --confirmation, --interactive
580 Ask for confirmation for every action.
581 -X filename, --exclude-from filename
583 Read a list of exclusion patterns from the specified file. See
584 --exclude for more information about the handling of exclusions.
585 --xattrs
587 (c, r, u, x modes only) Archive or extract extended attributes.
588 This is the reverse of --no-xattrs and the default behavior in c,
589 r, and u modes or if bsdtar is run in x mode as root.
590 -y (c mode only) Compress the resulting archive with bzip2(1). In
592 extract or list modes, this option is ignored. Note that this
593 tar implementation recognizes bzip2 compression automatically
594 when reading archives.
595 -Z, --compress, --uncompress
597 (c mode only) Compress the resulting archive with compress(1).
598 In extract or list modes, this option is ignored. Note that this
599 tar implementation recognizes compress compression automatically
600 when reading archives.
601 -z, --gunzip, --gzip
603 (c mode only) Compress the resulting archive with gzip(1). In
604 extract or list modes, this option is ignored. Note that this
605 tar implementation recognizes gzip compression automatically when
606 reading archives.
607
609 The following environment variables affect the execution of bsdtar:
610 TAR_READER_OPTIONS
612 The default options for format readers and compression read‐
613 ers. The --options option overrides this.
614 TAR_WRITER_OPTIONS
616 The default options for format writers and compression writ‐
617 ers. The --options option overrides this.
618 LANG The locale to use. See environ(7) for more information.
620 TAPE The default device. The -f option overrides this. Please see
622 the description of the -f option above for more details.
623 TZ The timezone to use when displaying dates. See environ(7) for
625 more information.
626
628 The bsdtar utility exits 0 on success, and >0 if an error occurs.
629
631 The following creates a new archive called file.tar.gz that contains two
632 files source.c and source.h:
633 bsdtar -czf file.tar.gz source.c source.h
634 To view a detailed table of contents for this archive:
636 bsdtar -tvf file.tar.gz
637 To extract all entries from the archive on the default tape drive:
639 bsdtar -x
640 To examine the contents of an ISO 9660 cdrom image:
642 bsdtar -tf image.iso
643 To move file hierarchies, invoke bsdtar as
645 bsdtar -cf - -C srcdir . | bsdtar -xpf - -C destdir
646 or more traditionally
647 cd srcdir ; bsdtar -cf - . | (cd destdir ; bsdtar -xpf -)
648 In create mode, the list of files and directories to be archived can also
650 include directory change instructions of the form -Cfoo/baz and archive
651 inclusions of the form @archive-file. For example, the command line
652 bsdtar -c -f new.tar foo1 @old.tgz -C/tmp foo2
653 will create a new archive new.tar. bsdtar will read the file foo1 from
654 the current directory and add it to the output archive. It will then
655 read each entry from old.tgz and add those entries to the output archive.
656 Finally, it will switch to the /tmp directory and add foo2 to the output
657 archive.
658 An input file in mtree(5) format can be used to create an output archive
660 with arbitrary ownership, permissions, or names that differ from existing
661 data on disk:
662 $ cat input.mtree
664 #mtree
665 usr/bin uid=0 gid=0 mode=0755 type=dir
666 usr/bin/ls uid=0 gid=0 mode=0755 type=file content=myls
667 $ tar -cvf output.tar @input.mtree
668 The --newer and --newer-mtime switches accept a variety of common date
670 and time specifications, including “12 Mar 2005 7:14:29pm”, “2005-03-12
671 19:14”, “5 minutes ago”, and “19:14 PST May 1”.
672 The --options argument can be used to control various details of archive
674 generation or reading. For example, you can generate mtree output which
675 only contains type, time, and uid keywords:
676 bsdtar -cf file.tar --format=mtree --options='!all,type,time,uid'
677 dir
678 or you can set the compression level used by gzip or xz compression:
679 bsdtar -czf file.tar --options='compression-level=9'.
680 For more details, see the explanation of the archive_read_set_options()
681 and archive_write_set_options() API calls that are described in
682 archive_read(3) and archive_write(3).
683
685 The bundled-arguments format is supported for compatibility with historic
686 implementations. It consists of an initial word (with no leading - char‐
687 acter) in which each character indicates an option. Arguments follow as
688 separate words. The order of the arguments must match the order of the
689 corresponding characters in the bundled command word. For example,
690 bsdtar tbf 32 file.tar
691 specifies three flags t, b, and f. The b and f flags both require argu‐
692 ments, so there must be two additional items on the command line. The 32
693 is the argument to the b flag, and file.tar is the argument to the f
694 flag.
695 The mode options c, r, t, u, and x and the options b, f, l, m, o, v, and
697 w comply with SUSv2.
698 For maximum portability, scripts that invoke tar should use the bundled-
700 argument format above, should limit themselves to the c, t, and x modes,
701 and the b, f, m, v, and w options.
702 Additional long options are provided to improve compatibility with other
704 tar implementations.
705
707 Certain security issues are common to many archiving programs, including
708 bsdtar. In particular, carefully-crafted archives can request that
709 bsdtar extract files to locations outside of the target directory. This
710 can potentially be used to cause unwitting users to overwrite files they
711 did not intend to overwrite. If the archive is being extracted by the
712 superuser, any file on the system can potentially be overwritten. There
713 are three ways this can happen. Although bsdtar has mechanisms to pro‐
714 tect against each one, savvy users should be aware of the implications:
715 · Archive entries can have absolute pathnames. By default, bsdtar
717 removes the leading / character from filenames before restoring
718 them to guard against this problem.
719 · Archive entries can have pathnames that include .. components.
721 By default, bsdtar will not extract files containing .. compo‐
722 nents in their pathname.
723 · Archive entries can exploit symbolic links to restore files to
725 other directories. An archive can restore a symbolic link to
726 another directory, then use that link to restore a file into that
727 directory. To guard against this, bsdtar checks each extracted
728 path for symlinks. If the final path element is a symlink, it
729 will be removed and replaced with the archive entry. If -U is
730 specified, any intermediate symlink will also be unconditionally
731 removed. If neither -U nor -P is specified, bsdtar will refuse
732 to extract the entry.
733 To protect yourself, you should be wary of any archives that come from
734 untrusted sources. You should examine the contents of an archive with
735 bsdtar -tf filename
736 before extraction. You should use the -k option to ensure that bsdtar
737 will not overwrite any existing files or the -U option to remove any pre-
738 existing files. You should generally not extract archives while running
739 with super-user privileges. Note that the -P option to bsdtar disables
740 the security checks above and allows you to extract an archive while pre‐
741 serving any absolute pathnames, .. components, or symlinks to other
742 directories.
743
745 bzip2(1), compress(1), cpio(1), gzip(1), mt(1), pax(1), shar(1), xz(1),
746 libarchive(3), libarchive-formats(5), tar(5)
747
749 There is no current POSIX standard for the tar command; it appeared in
750 ISO/IEC 9945-1:1996 (“POSIX.1”) but was dropped from IEEE Std 1003.1-2001
751 (“POSIX.1”). The options supported by this implementation were developed
752 by surveying a number of existing tar implementations as well as the old
753 POSIX specification for tar and the current POSIX specification for pax.
754 The ustar and pax interchange file formats are defined by IEEE Std
756 1003.1-2001 (“POSIX.1”) for the pax command.
757
759 A tar command appeared in Seventh Edition Unix, which was released in
760 January, 1979. There have been numerous other implementations, many of
761 which extended the file format. John Gilmore's pdtar public-domain
762 implementation (circa November, 1987) was quite influential, and formed
763 the basis of GNU tar. GNU tar was included as the standard system tar in
764 FreeBSD beginning with FreeBSD 1.0.
765 This is a complete re-implementation based on the libarchive(3) library.
767 It was first released with FreeBSD 5.4 in May, 2005.
768
770 This program follows ISO/IEC 9945-1:1996 (“POSIX.1”) for the definition
771 of the -l option. Note that GNU tar prior to version 1.15 treated -l as
772 a synonym for the --one-file-system option.
773 The -C dir option may differ from historic implementations.
775 All archive output is written in correctly-sized blocks, even if the out‐
777 put is being compressed. Whether or not the last output block is padded
778 to a full block size varies depending on the format and the output
779 device. For tar and cpio formats, the last block of output is padded to
780 a full block size if the output is being written to standard output or to
781 a character or block device such as a tape drive. If the output is being
782 written to a regular file, the last block will not be padded. Many com‐
783 pressors, including gzip(1) and bzip2(1), complain about the null padding
784 when decompressing an archive created by bsdtar, although they still
785 extract it correctly.
786 The compression and decompression is implemented internally, so there may
788 be insignificant differences between the compressed output generated by
789 bsdtar -czf - file
790 and that generated by
791 bsdtar -cf - file | gzip
792 The default should be to read and write archives to the standard I/O
794 paths, but tradition (and POSIX) dictates otherwise.
795 The r and u modes require that the archive be uncompressed and located in
797 a regular file on disk. Other archives can be modified using c mode with
798 the @archive-file extension.
799 To archive a file called @foo or -foo you must specify it as ./@foo or
801 ./-foo, respectively.
802 In create mode, a leading ./ is always removed. A leading / is stripped
804 unless the -P option is specified.
805 There needs to be better support for file selection on both create and
807 extract.
808 There is not yet any support for multi-volume archives.
810 Converting between dissimilar archive formats (such as tar and cpio)
812 using the @- convention can cause hard link information to be lost.
813 (This is a consequence of the incompatible ways that different archive
814 formats store hardlink information.)
815BSD October 1, 2017 BSD