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-
- NAME
- tar - media file archiver
-
- SYNOPSIS
- tar -[BcDhikmopstvxzZ] [-b N] [-f F] [-T F] [ filename ... ]
-
- DESCRIPTION
- tar provides a way to store many files into a single
- archive, which can be kept in another file, stored on
- an I/O device such as tape, floppy, cartridge, or disk, or
- piped to another program. It is useful for making backup
- copies, or for packaging up a set of files to move them to
- another system.
-
- When reading an archive, this version of tar continues after
- finding an error. Previous versions required the `i' option
- to ignore checksum errors.
-
- OPTIONS
- tar options can be specified in either of two ways. The
- usual Unix conventions can be used: each option is preceded
- by `-'; arguments directly follow each option; multiple
- options can be combined behind one `-' as long as they take
- no arguments. For compatability with the Unix tar program,
- the options may also be specified as ``keyletters,'' wherein
- all the option letters occur in the first argument to tar,
- with no `-', and their arguments, if any, occur in the
- second, third, ... arguments. Examples:
-
- Normal: tar -f arcname -cv file1 file2
-
- Old: tar fcv arcname file1 file2
-
- At least one of the -c, -t, or -x options must be included.
- The rest are optional.
-
- Files to be operated upon are specified by a list of file
- names, which follows the option specifications (or can be
- read from a file by the -T option). Specifying a directory
- name causes that directory and all the files it contains to
- be (recursively) processed. In general, specifying full
- path names when creating an archive is a bad idea, since
- when the files are extracted, they will have to be extracted
- into exactly where they were dumped from. Instead, cd to
- the root directory and use relative file names.
-
- -b N Specify a blocking factor for the archive. The block
- size will be N x 512 bytes. Larger blocks typically
- run faster and let you fit more data on a tape. The
- default blocking factor is set when tar is compiled,
- and is typically 20. There is no limit to the maximum
- block size, as long as enough memory can be allocated
- for it, and as long as the device containing the
- archive can read or write that block size.
-
- -B When reading an archive, reblock it as we read it.
- Normally, tar reads each block with a single read(2)
- system call. This does not work when reading from a
- pipe or network socket under Berkeley Unix. With this
- option, it will do multiple read(2)s until it gets
- enough data to fill the specified block size. -B can
- also be used to speed up the reading of tapes that were
- written with small blocking factors, by specifying a
- large blocking factor with -b and having tar read many
- small blocks into memory before it tries to process
- them.
-
- -c Create an archive from a list of files.
-
- -D With each message that tar produces, print the record
- number within the archive where the message occurred.
- This option is especially useful when reading damaged
- archives, since it helps to pinpoint the damaged sec-
- tion.
-
- -f F Specify the filename of the archive. If the specified
- filename is ``-'', the archive is read from the stan-
- dard input or written to the standard output. If this
- option is not used, a default archive name (which was
- picked when tar was compiled) is used. The default is
- normally set to the ``first'' tape drive or other tran-
- sportable I/O medium on the system.
-
- -h When creating an archive, if a symbolic link is encoun-
- tered, dump the file or directory to which it points,
- rather than dumping it as a symbolic link.
-
- -i When reading an archive, ignore blocks of zeros in the
- archive. Normally a block of zeros indicates the end
- of the archive, but in a damaged archive, or one which
- was created by appending several archives, this option
- allows tar to continue. It is not on by default
- because there is garbage written after the zeroed
- blocks by the Unix tar program.
-
- -k When extracting files from an archive, keep existing
- files, rather than overwriting them with the version
- from the archive.
-
- -m When extracting files from an archive, set each file's
- modified timestamp to the current time, rather than
- extracting each file's modified timestamp from the
- archive.
-
- -o When creating an archive, write an old format archive,
- which does not include information about directories,
- pipes, or device files, and specifies file ownership by
- uid's and gid's rather than by user names and group
- names. In most cases, a ``new'' format archive can be
- read by an ``old'' tar program without serious trouble,
- so this option should seldom be needed.
-
- -p When extracting files from an archive, restore them to
- the same permissions that they had in the archive. If
- -p is not specified, the current umask limits the per-
- missions of the extracted files. See umask(2).
-
- -t List a table of contents of an existing archive. If
- file names are specified, just list files matching the
- specified names.
-
- -s When specifying a list of filenames to be listed or
- extracted from an archive, the -s flag specifies that
- the list is sorted into the same order as the tape.
- This allows a large list to be used, even on small
- machines, because the entire list need not be read into
- memory at once. Such a sorted list can easily be
- created by running ``tar -t'' on the archive and edit-
- ing its output.
-
- -T F Rather than specifying the file names to operate on as
- arguments to the tar command, this option specifies
- that the file names should be read from the file F, one
- per line. If the file name specified is ``-'', the
- list is read from the standard input. This option, in
- conjunction with the -s option, allows an arbitrarily
- large list of files to be processed, and allows the
- list to be piped to tar.
-
- -v Be verbose about the files that are being processed or
- listed. Normally, archive creation or file extraction
- are silent, and archive listing just gives file names.
- The -v option causes an ``ls -l''-like listing to be
- produced.
-
- -x Extract files from an existing archive. If file name
- are specified, just extract files matching the speci-
- fied names, otherwise extract all the files in the
- archive.
-
- -z or -Z
- When extracting or listing an archive, these options
- specify that the archive should be decompressed while
- it is read, using the -d option of the compress(1) pro-
- gram. The archive itself is not modified.
-
- BUGS
- The r, u, w, X, l, F, C, and digit options of Unix tar are
- not supported.
-
- It should be possible to create a compressed archive with
- the -z option.
-
-
- NOTES ON AMIGA VERSION:
-
- The following notes appeared together with the GCC port of V1.09.
- You'd have to check out by yourself, whether these are still
- valid for the SAS/C V1.11.2 port. -AK, 16 Sep 95
-
- Addendum for Version 1.1:
-
- The -p option for extracting files with their dates
- preserved is now supported (under AmigaDos 1.2 only; do not
- try to use this option under AmigaDos 1.1).
-
- Addendum for Version 1.2:
-
- The -p option now works on floppies as well as ram:. Various
- internal hacking has been done, and things are slightly
- different than before. The date conversion is now aware that
- it's summertime, and not wintertime (a change noticble only
- to people who've been porting tar archives back and forth
- between Unix and the Amiga).
-