TAR(1)TAR(1)NAME
tar, dircp - archiver
SYNOPSIS
tar key [ file ... ]
dircp fromdir todir
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 sub‐
directories (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 direc‐
tory, 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.
i Ignore errors encountered when reading. Errors writing either
produce a corrupt archive or indicate deeper file system prob‐
lems.
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 compat‐
ibility 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.
s When extracting, attempt to resynchronise after not finding a
tape header block where expected.
T Modifies the behavior of x to set the modified time, mode and,
for POSIX archives and filesystem permitting, the user and group
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 as it is processed. 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 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 c .} | @{cd todir && tar xT}
Dircp does this.
SOURCE
/sys/src/cmd/tar.c
/rc/bin/dircp
SEE ALSOar(1), bundle(1), tapefs(4), mkfs(8)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, con‐
cepts foreign to Plan 9: they are ignored.
The r key (append) cannot be used on compressed archives.
Tar, thus dircp, doesn't record Plan-9-specific metadata such as
append-only and exclusive-open permission bits, so they aren't copied.
TAR(1)
