|  | 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.
 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 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.
 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. 
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