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 subdirec-
          tories (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 con-
               tains 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 problems.

          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

     TAR(1)                                                     TAR(1)

               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 read-
               ing archives.  This is the default behavior; the flag
               exists only for backwards compatibility with older ver-
               sions 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 pro-
               cessed.  With t, give more details about the archive
               entries.

          z    Operate on compressed tar archives.  The type of com-
               pression 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 ALSO
          ar(1), bundle(1), tapefs(4), mkfs(8)

     TAR(1)                                                     TAR(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.

          Tar, thus dircp, doesn't record Plan-9-specific metadata
          such as append-only and exclusive-open permission bits, so
          they aren't copied.