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1 .\" $NetBSD: tar.1,v 1.26 2007/12/02 21:14:49 wiz Exp $
2 .\"
3 .\" Copyright (c) 1996 SigmaSoft, Th. Lockert
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17 .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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26 .\" OpenBSD: tar.1,v 1.28 2000/11/09 23:58:56 aaron Exp
27 .\"
28 .Dd May 4, 2007
29 .Dt TAR 1
30 .Os
31 .Sh NAME
32 .Nm tar
33 .Nd tape archiver
34 .Sh SYNOPSIS
35 .Nm tar
36 .Sm off
37 .Oo \&- Oc {crtux} Op Fl 014578befHhjklmOoPpqSvwXZz
38 .Sm on
39 .Op Ar archive
40 .Op Ar blocksize
41 .\" XXX how to do this right?
42 .Op Fl C Ar directory
43 .Op Fl s Ar replstr
44 .Op Fl T Ar file
45 .Op Ar file ...
46 .Sh DESCRIPTION
47 The
48 .Nm
49 command creates, adds files to, or extracts files from an
50 archive file in
51 .Dq tar
52 format.
53 A tar archive is often stored on a magnetic tape, but can be
54 stored equally well on a floppy, CD-ROM, or in a regular disk file.
55 .Pp
56 One of the following flags must be present:
57 .Bl -tag -width Ar
58 .It Fl c , -create
59 Create new archive, or overwrite an existing archive,
60 adding the specified files to it.
61 .It Fl r , -append
62 Append the named new files to existing archive.
63 Note that this will only work on media on which an end-of-file mark
64 can be overwritten.
65 .It Fl t , -list
66 List contents of archive.
67 If any files are named on the
68 command line, only those files will be listed.
69 .It Fl u , -update
70 Alias for
71 .Fl r .
72 .It Fl x , -extract , -get
73 Extract files from archive.
74 If any files are named on the
75 command line, only those files will be extracted from the
76 archive.
77 If more than one copy of a file exists in the
78 archive, later copies will overwrite earlier copies during
79 extraction.
80 The file mode and modification time are preserved
81 if possible.
82 The file mode is subject to modification by the
83 .Xr umask 2 .
84 .El
85 .Pp
86 In addition to the flags mentioned above, any of the following
87 flags may be used:
88 .Bl -tag -width Ar
89 .It Fl b Ar "blocking factor" , Fl -block-size Ar "blocking factor"
90 Set blocking factor to use for the archive.
91 .Nm
92 uses 512 byte blocks.
93 The default is 20, the maximum is 126.
94 Archives with a blocking factor larger 63 violate the
95 .Tn POSIX
96 standard and will not be portable to all systems.
97 .It Fl e
98 Stop after first error.
99 .It Fl f Ar archive , Fl -file Ar archive
100 Filename where the archive is stored.
101 Defaults to
102 .Pa /dev/rst0 .
103 If the archive is of the form:
104 .Ar [[user@]host:]file
105 then the archive will be processed using
106 .Xr rmt 8 .
107 .It Fl h , -dereference
108 Follow symbolic links as if they were normal files
109 or directories.
110 .It Fl j, -bzip2, -bunzip2
111 Use
112 .Xr bzip2 1
113 for compression of the archive.
114 This option is a GNU extension.
115 .It Fl k , -keep-old-files
116 Keep existing files; don't overwrite them from archive.
117 .It Fl l , -one-file-system
118 Do not descend across mount points.
119 .\" should be '-X'
120 .It Fl m , -modification-time
121 Do not preserve modification time.
122 .It Fl O
123 When creating and appending to an archive, write old-style (non-POSIX) archives.
124 When extracting from an archive, extract to standard output.
125 .It Fl o , -portability , -old-archive
126 Don't write directory information that the older (V7) style
127 .Nm
128 is unable to decode.
129 This implies the
130 .Fl O
131 flag.
132 .It Fl p , -preserve-permissions , -preserve
133 Preserve user and group ID as well as file mode regardless of
134 the current
135 .Xr umask 2 .
136 The setuid and setgid bits are only preserved if the user is
137 the superuser.
138 Only meaningful in conjunction with the
139 .Fl x
140 flag.
141 .It Fl q , -fast-read
142 Select the first archive member that matches each
143 .Ar pattern
144 operand.
145 No more than one archive member is matched for each
146 .Ar pattern .
147 When members of type directory are matched, the file hierarchy rooted at that
148 directory is also matched.
149 .It Fl S , -sparse
150 This flag has no effect as
151 .Nm
152 always generates sparse files.
153 .It Fl s Ar replstr
154 Modify the file or archive member names specified by the
155 .Ar pattern
156 or
157 .Ar file
158 operands according to the substitution expression
159 .Ar replstr ,
160 using the syntax of the
161 .Xr ed 1
162 utility regular expressions.
163 The format of these regular expressions are:
164 .Dl /old/new/[gps]
165 As in
166 .Xr ed 1 ,
167 .Cm old
168 is a basic regular expression and
169 .Cm new
170 can contain an ampersand (\*[Am]), \\n (where n is a digit) back-references,
171 or subexpression matching.
172 The
173 .Cm old
174 string may also contain
175 .Aq Dv newline
176 characters.
177 Any non-null character can be used as a delimiter (/ is shown here).
178 Multiple
179 .Fl s
180 expressions can be specified.
181 The expressions are applied in the order they are specified on the
182 command line, terminating with the first successful substitution.
183 The optional trailing
184 .Cm g
185 continues to apply the substitution expression to the pathname substring
186 which starts with the first character following the end of the last successful
187 substitution.
188 The first unsuccessful substitution stops the operation of the
189 .Cm g
190 option.
191 The optional trailing
192 .Cm p
193 will cause the final result of a successful substitution to be written to
194 .Dv standard error
195 in the following format:
196 .Dl \*[Lt]original pathname\*[Gt] \*[Gt]\*[Gt] \*[Lt]new pathname\*[Gt]
197 File or archive member names that substitute to the empty string
198 are not selected and will be skipped.
199 The substitutions are applied by default to the destination hard and symbolic
200 links.
201 The optional trailing
202 .Cm s
203 prevents the substitutions from being performed on symbolic link destinations.
204 .It Fl v
205 Verbose operation mode.
206 .It Fl w , -interactive , -confirmation
207 Interactively rename files.
208 This option causes
209 .Nm
210 to prompt the user for the filename to use when storing or
211 extracting files in an archive.
212 .It Fl z , -gzip , -gunzip
213 Compress archive using gzip.
214 .It Fl B , -read-full-blocks
215 Reassemble small reads into full blocks (For reading from 4.2BSD pipes).
216 .It Fl C Ar directory , Fl -directory Ar directory
217 This is a positional argument which sets the working directory for the
218 following files.
219 When extracting, files will be extracted into
220 the specified directory; when creating, the specified files will be matched
221 from the directory.
222 This argument and its parameter may also appear in a file list specified by
223 .Fl T .
224 .It Fl H
225 Only follow symlinks given on command line.
226 .Pp
227 Note SysVr3/i386 picked up ISC/SCO UNIX compatibility which implemented
228 .Dq Fl F Ar file
229 which was defined as obtaining a list of command line switches and files
230 on which to operate from the specified file,
231 but SunOS-5 uses
232 .Dq Fl I Ar file
233 because they use
234 .Sq Fl F
235 to mean something else.
236 We might someday provide SunOS-5 compatibility
237 but it makes little sense to confuse things with ISC/SCO compatibility.
238 .\".It Fl L
239 .\"Do not follow any symlinks (do the opposite of
240 .\".Fl h ).
241 .It Fl P , -absolute-paths
242 Do not strip leading slashes
243 .Pq Sq /
244 from pathnames.
245 The default is to strip leading slashes.
246 .It Fl T Ar file , Fl -files-from Ar file
247 Read the names of files to archive or extract from the given file, one
248 per line.
249 A line may also specify the positional argument
250 .Dq Fl C Ar directory .
251 .It Fl X Ar file , Fl -exclude-from Ar file
252 Exclude files listed in the given file.
253 .\" exclude should be '-E' and '-X' should be one-file-system
254 .Pp
255 Note that it would be more standard to use this option to mean ``do not
256 cross filesystem mount points.''
257 .It Fl Z , -compress , -uncompress
258 Compress archive using compress.
259 .It Fl -strict
260 Do not enable GNU tar extensions such as long filenames and long link names.
261 .It Fl -atime-preserve
262 Preserve file access times.
263 .It Fl -chroot
264 .Fn chroot
265 to the current directory before extracting files.
266 Use with
267 .Fl x
268 and
269 .Fl h
270 to make absolute symlinks relative to the current directory.
271 .It Fl -unlink
272 Ignored, only accepted for compatibility with other
273 .Nm
274 implementations.
275 .Nm
276 always unlinks files before creating them.
277 .It Fl -use-compress-program Ar program
278 Use the named program as the program to decompress the input.
279 .It Fl -force-local
280 Do not interpret filenames that contain a
281 .Sq \&:
282 as remote files.
283 .It Fl -insecure
284 Normally
285 .Nm
286 ignores filenames that contain
287 .Dq ..
288 as a path component.
289 With this option, files that contain
290 .Dq ..
291 can be processed.
292 .It Fl -no-recursion
293 Cause files of type directory being copied or archived, or archive members of
294 type directory being extracted, to match only the directory file or archive
295 member and not the file hierarchy rooted at the directory.
296 .El
297 .Pp
298 The options
299 .Op Fl 014578
300 can be used to select one of the compiled-in backup devices,
301 .Pa /dev/rstN .
302 .Sh FILES
303 .Bl -tag -width "/dev/rst0"
304 .It Pa /dev/rst0
305 default archive name
306 .El
307 .Sh DIAGNOSTICS
308 .Nm
309 will exit with one of the following values:
310 .Bl -tag -width 2n
311 .It 0
312 All files were processed successfully.
313 .It 1
314 An error occurred.
315 .El
316 .Pp
317 Whenever
318 .Nm
319 cannot create a file or a link when extracting an archive or cannot
320 find a file while writing an archive, or cannot preserve the user
321 ID, group ID, file mode, or access and modification times when the
322 .Fl p
323 option is specified, a diagnostic message is written to standard
324 error and a non-zero exit value will be returned, but processing
325 will continue.
326 In the case where
327 .Nm
328 cannot create a link to a file,
329 .Nm
330 will not create a second copy of the file.
331 .Pp
332 If the extraction of a file from an archive is prematurely terminated
333 by a signal or error,
334 .Nm
335 may have only partially extracted the file the user wanted.
336 Additionally, the file modes of extracted files and directories may
337 have incorrect file bits, and the modification and access times may
338 be wrong.
339 .Pp
340 If the creation of an archive is prematurely terminated by a signal
341 or error,
342 .Nm
343 may have only partially created the archive which may violate the
344 specific archive format specification.
345 .Sh SEE ALSO
346 .Xr cpio 1 ,
347 .Xr pax 1
348 .Sh HISTORY
349 A
350 .Nm
351 command first appeared in
352 .At v7 .
353 .Sh AUTHORS
354 Keith Muller at the University of California, San Diego.