NAME

tar − archiver

SYNOPSIS

­tar ­key [ ­file ...  ]

DESCRIPTION

­Tar saves and restores file trees.  It is most often used to transport a tree of files from one system to another.  The ­key is a string that contains at most one function letter plus optional modifiers.  Other arguments to the command are names of files or directories to be dumped or restored.  A directory name implies all the contained files and subdirectories (recursively). 

The function is one of the following letters:

­c Create a new archive with the given files as contents. 

­r The named files are appended to the archive. 

­t List all occurrences of each ­file in the archive, or of all files if there are no ­file arguments. 

­x Extract the named files from the archive.  If a file is a directory, the directory is extracted recursively.  Modes are restored if possible.  If no file argument is given, extract the entire archive.  If the archive contains multiple entries for a file, the latest one wins. 

The modifiers are:

­f Use the next argument as the name of the archive instead of the default standard input (for keys ­x and t) or standard output (for keys ­c and r). 

­g Use the next (numeric) argument as the group id for files in the output archive. 

­k (keep) Modifies the behavior of ­x not to extract files which already exist. 

­m Do not set the modification time on extracted files.  This is the default behavior; the flag exists only for compatibility with other tars. 

­p Create archive in POSIX ustar format, which raises the maximum pathname length from 100 to 256 bytes.  Ustar archives are recognised automatically by ­tar when reading archives.  This is the default behavior; the flag exists only for backwards compatibility with older versions of tar. 

­P Do not generate the POSIX ustar format. 

­R When extracting, respect leading slash on file names.  By default, files are always extracted relative to the current directory. 

­T Modifies the behavior of ­x to set the modified time of each file to that specified in the archive. 

­u Use the next (numeric) argument as the user id for files in the output archive.  This is only useful when moving files to a non-Plan 9 system. 

­v (verbose) Print the name of each file treated preceded by the function letter.  With t, give more details about the archive entries. 

­z Operate on compressed tar archives.  The type of compression is inferred from the file name extension: gzip(1) for ­.tar.gz and .tgz; ­bzip2 (see gzip(1)) for .tar.bz, .tbz, .tar.bz2, and .tbz2; ­compress (not distributed) for ­.tar.Z and .tz.  If no extension matches, ­gzip is used.  The ­z flag is unnecessary (but allowed) when using the ­t and ­x verbs on archives with recognized extensions. 

EXAMPLES

­Tar can be used to copy hierarchies thus:

@{cd fromdir && tar cp .} | @{cd todir && tar xT}

SOURCE

­/sys/src/cmd/tar.c

SEE ALSO

ar(1), bundle(1), tapefs(1)

BUGS

There is no way to ask for any but the last occurrence of a file. 

File path names are limited to 100 characters (256 when using ustar format). 

The tar format allows specification of links and symbolic links, concepts foreign to Plan 9: they are ignored. 

The ­r key (append) cannot be used on compressed archives. 

Plan 9  —  June 28, 2005