Archive::Tar - man - phpMan

 


Archive::Tar
NAME SYNOPSIS DESCRIPTION Object Methods Class Methods GLOBAL VARIABLES FAQ CAVEATS TODO SEE ALSO AUTHOR ACKNOWLEDGEMENTS COPYRIGHT
NAME
    Archive::Tar - module for manipulations of tar archives

SYNOPSIS
        use Archive::Tar;
        my $tar = Archive::Tar->new;

        $tar->read('origin.tgz');
        $tar->extract();

        $tar->add_files('file/foo.pl', 'docs/README');
        $tar->add_data('file/baz.txt', 'This is the contents now');

        $tar->rename('oldname', 'new/file/name');
        $tar->chown('/', 'root');
        $tar->chown('/', 'root:root');
        $tar->chmod('/tmp', '1777');

        $tar->write('files.tar');                   # plain tar
        $tar->write('files.tgz', COMPRESS_GZIP);    # gzip compressed
        $tar->write('files.tbz', COMPRESS_BZIP);    # bzip2 compressed
        $tar->write('files.txz', COMPRESS_XZ);      # xz compressed

DESCRIPTION
    Archive::Tar provides an object oriented mechanism for handling tar
    files. It provides class methods for quick and easy files handling while
    also allowing for the creation of tar file objects for custom
    manipulation. If you have the IO::Zlib module installed, Archive::Tar
    will also support compressed or gzipped tar files.

    An object of class Archive::Tar represents a .tar(.gz) archive full of
    files and things.

Object Methods
  Archive::Tar->new( [$file, $compressed] )
    Returns a new Tar object. If given any arguments, "new()" calls the
    "read()" method automatically, passing on the arguments provided to the
    "read()" method.

    If "new()" is invoked with arguments and the "read()" method fails for
    any reason, "new()" returns undef.

  $tar->read ( $filename|$handle, [$compressed, {opt => 'val'}] )
    Read the given tar file into memory. The first argument can either be
    the name of a file or a reference to an already open filehandle (or an
    IO::Zlib object if it's compressed)

    The "read" will *replace* any previous content in $tar!

    The second argument may be considered optional, but remains for
    backwards compatibility. Archive::Tar now looks at the file magic to
    determine what class should be used to open the file and will
    transparently Do The Right Thing.

    Archive::Tar will warn if you try to pass a bzip2 / xz compressed file
    and the IO::Uncompress::Bunzip2 / IO::Uncompress::UnXz are not available
    and simply return.

    Note that you can currently not pass a "gzip" compressed filehandle,
    which is not opened with "IO::Zlib", a "bzip2" compressed filehandle,
    which is not opened with "IO::Uncompress::Bunzip2", a "xz" compressed
    filehandle, which is not opened with "IO::Uncompress::UnXz", nor a
    string containing the full archive information (either compressed or
    uncompressed). These are worth while features, but not currently
    implemented. See the "TODO" section.

    The third argument can be a hash reference with options. Note that all
    options are case-sensitive.

    limit
        Do not read more than "limit" files. This is useful if you have very
        big archives, and are only interested in the first few files.

    filter
        Can be set to a regular expression. Only files with names that match
        the expression will be read.

    md5 Set to 1 and the md5sum of files will be returned (instead of file
        data) my $iter = Archive::Tar->iter( $file, 1, {md5 => 1} ); while(
        my $f = $iter->() ) { print $f->data . "\t" . $f->full_path . $/; }

    extract
        If set to true, immediately extract entries when reading them. This
        gives you the same memory break as the "extract_archive" function.
        Note however that entries will not be read into memory, but written
        straight to disk. This means no "Archive::Tar::File" objects are
        created for you to inspect.

    All files are stored internally as "Archive::Tar::File" objects. Please
    consult the Archive::Tar::File documentation for details.

    Returns the number of files read in scalar context, and a list of
    "Archive::Tar::File" objects in list context.

  $tar->contains_file( $filename )
    Check if the archive contains a certain file. It will return true if the
    file is in the archive, false otherwise.

    Note however, that this function does an exact match using "eq" on the
    full path. So it cannot compensate for case-insensitive file- systems or
    compare 2 paths to see if they would point to the same underlying file.

  $tar->extract( [@filenames] )
    Write files whose names are equivalent to any of the names in @filenames
    to disk, creating subdirectories as necessary. This might not work too
    well under VMS. Under MacPerl, the file's modification time will be
    converted to the MacOS zero of time, and appropriate conversions will be
    done to the path. However, the length of each element of the path is not
    inspected to see whether it's longer than MacOS currently allows (32
    characters).

    If "extract" is called without a list of file names, the entire contents
    of the archive are extracted.

    Returns a list of filenames extracted.

  $tar->extract_file( $file, [$extract_path] )
    Write an entry, whose name is equivalent to the file name provided to
    disk. Optionally takes a second parameter, which is the full native path
    (including filename) the entry will be written to.

    For example:

        $tar->extract_file( 'name/in/archive', 'name/i/want/to/give/it' );

        $tar->extract_file( $at_file_object,   'name/i/want/to/give/it' );

    Returns true on success, false on failure.

  $tar->list_files( [\@properties] )
    Returns a list of the names of all the files in the archive.

    If "list_files()" is passed an array reference as its first argument it
    returns a list of hash references containing the requested properties of
    each file. The following list of properties is supported: name, size,
    mtime (last modified date), mode, uid, gid, linkname, uname, gname,
    devmajor, devminor, prefix.

    Passing an array reference containing only one element, 'name', is
    special cased to return a list of names rather than a list of hash
    references, making it equivalent to calling "list_files" without
    arguments.

  $tar->get_files( [@filenames] )
    Returns the "Archive::Tar::File" objects matching the filenames
    provided. If no filename list was passed, all "Archive::Tar::File"
    objects in the current Tar object are returned.

    Please refer to the "Archive::Tar::File" documentation on how to handle
    these objects.

  $tar->get_content( $file )
    Return the content of the named file.

  $tar->replace_content( $file, $content )
    Make the string $content be the content for the file named $file.

  $tar->rename( $file, $new_name )
    Rename the file of the in-memory archive to $new_name.

    Note that you must specify a Unix path for $new_name, since per tar
    standard, all files in the archive must be Unix paths.

    Returns true on success and false on failure.

  $tar->chmod( $file, $mode )
    Change mode of $file to $mode.

    Returns true on success and false on failure.

  $tar->chown( $file, $uname [, $gname] )
    Change owner $file to $uname and $gname.

    Returns true on success and false on failure.

  $tar->remove (@filenamelist)
    Removes any entries with names matching any of the given filenames from
    the in-memory archive. Returns a list of "Archive::Tar::File" objects
    that remain.

  $tar->clear
    "clear" clears the current in-memory archive. This effectively gives you
    a 'blank' object, ready to be filled again. Note that "clear" only has
    effect on the object, not the underlying tarfile.

  $tar->write ( [$file, $compressed, $prefix] )
    Write the in-memory archive to disk. The first argument can either be
    the name of a file or a reference to an already open filehandle (a GLOB
    reference).

    The second argument is used to indicate compression. You can compress
    using "gzip", "bzip2" or "xz". If you pass a digit, it's assumed to be
    the "gzip" compression level (between 1 and 9), but the use of constants
    is preferred:

      # write a gzip compressed file
      $tar->write( 'out.tgz', COMPRESS_GZIP );

      # write a bzip compressed file
      $tar->write( 'out.tbz', COMPRESS_BZIP );

      # write a xz compressed file
      $tar->write( 'out.txz', COMPRESS_XZ );

    Note that when you pass in a filehandle, the compression argument is
    ignored, as all files are printed verbatim to your filehandle. If you
    wish to enable compression with filehandles, use an "IO::Zlib",
    "IO::Compress::Bzip2" or "IO::Compress::Xz" filehandle instead.

    The third argument is an optional prefix. All files will be tucked away
    in the directory you specify as prefix. So if you have files 'a' and 'b'
    in your archive, and you specify 'foo' as prefix, they will be written
    to the archive as 'foo/a' and 'foo/b'.

    If no arguments are given, "write" returns the entire formatted archive
    as a string, which could be useful if you'd like to stuff the archive
    into a socket or a pipe to gzip or something.

  $tar->add_files( @filenamelist )
    Takes a list of filenames and adds them to the in-memory archive.

    The path to the file is automatically converted to a Unix like
    equivalent for use in the archive, and, if on MacOS, the file's
    modification time is converted from the MacOS epoch to the Unix epoch.
    So tar archives created on MacOS with Archive::Tar can be read both with
    *tar* on Unix and applications like *suntar* or *Stuffit Expander* on
    MacOS.

    Be aware that the file's type/creator and resource fork will be lost,
    which is usually what you want in cross-platform archives.

    Instead of a filename, you can also pass it an existing
    "Archive::Tar::File" object from, for example, another archive. The
    object will be clone, and effectively be a copy of the original, not an
    alias.

    Returns a list of "Archive::Tar::File" objects that were just added.

  $tar->add_data ( $filename, $data, [$opthashref] )
    Takes a filename, a scalar full of data and optionally a reference to a
    hash with specific options.

    Will add a file to the in-memory archive, with name $filename and
    content $data. Specific properties can be set using $opthashref. The
    following list of properties is supported: name, size, mtime (last
    modified date), mode, uid, gid, linkname, uname, gname, devmajor,
    devminor, prefix, type. (On MacOS, the file's path and modification
    times are converted to Unix equivalents.)

    Valid values for the file type are the following constants defined by
    Archive::Tar::Constant:

    FILE
        Regular file.

    HARDLINK
    SYMLINK
        Hard and symbolic ("soft") links; linkname should specify target.

    CHARDEV
    BLOCKDEV
        Character and block devices. devmajor and devminor should specify
        the major and minor device numbers.

    DIR Directory.

    FIFO
        FIFO (named pipe).

    SOCKET
        Socket.

    Returns the "Archive::Tar::File" object that was just added, or "undef"
    on failure.

  $tar->error( [$BOOL] )
    Returns the current error string (usually, the last error reported). If
    a true value was specified, it will give the "Carp::longmess" equivalent
    of the error, in effect giving you a stacktrace.

    For backwards compatibility, this error is also available as
    $Archive::Tar::error although it is much recommended you use the method
    call instead.

  $tar->setcwd( $cwd );
    "Archive::Tar" needs to know the current directory, and it will run
    "Cwd::cwd()" *every* time it extracts a *relative* entry from the
    tarfile and saves it in the file system. (As of version 1.30, however,
    "Archive::Tar" will use the speed optimization described below
    automatically, so it's only relevant if you're using "extract_file()").

    Since "Archive::Tar" doesn't change the current directory internally
    while it is extracting the items in a tarball, all calls to "Cwd::cwd()"
    can be avoided if we can guarantee that the current directory doesn't
    get changed externally.

    To use this performance boost, set the current directory via

        use Cwd;
        $tar->setcwd( cwd() );

    once before calling a function like "extract_file" and "Archive::Tar"
    will use the current directory setting from then on and won't call
    "Cwd::cwd()" internally.

    To switch back to the default behaviour, use

        $tar->setcwd( undef );

    and "Archive::Tar" will call "Cwd::cwd()" internally again.

    If you're using "Archive::Tar"'s "extract()" method, "setcwd()" will be
    called for you.

Class Methods
  Archive::Tar->create_archive($file, $compressed, @filelist)
    Creates a tar file from the list of files provided. The first argument
    can either be the name of the tar file to create or a reference to an
    open file handle (e.g. a GLOB reference).

    The second argument is used to indicate compression. You can compress
    using "gzip", "bzip2" or "xz". If you pass a digit, it's assumed to be
    the "gzip" compression level (between 1 and 9), but the use of constants
    is preferred:

      # write a gzip compressed file
      Archive::Tar->create_archive( 'out.tgz', COMPRESS_GZIP, @filelist );

      # write a bzip compressed file
      Archive::Tar->create_archive( 'out.tbz', COMPRESS_BZIP, @filelist );

      # write a xz compressed file
      Archive::Tar->create_archive( 'out.txz', COMPRESS_XZ, @filelist );

    Note that when you pass in a filehandle, the compression argument is
    ignored, as all files are printed verbatim to your filehandle. If you
    wish to enable compression with filehandles, use an "IO::Zlib",
    "IO::Compress::Bzip2" or "IO::Compress::Xz" filehandle instead.

    The remaining arguments list the files to be included in the tar file.
    These files must all exist. Any files which don't exist or can't be read
    are silently ignored.

    If the archive creation fails for any reason, "create_archive" will
    return false. Please use the "error" method to find the cause of the
    failure.

    Note that this method does not write "on the fly" as it were; it still
    reads all the files into memory before writing out the archive. Consult
    the FAQ below if this is a problem.

  Archive::Tar->iter( $filename, [ $compressed, {opt => $val} ] )
    Returns an iterator function that reads the tar file without loading it
    all in memory. Each time the function is called it will return the next
    file in the tarball. The files are returned as "Archive::Tar::File"
    objects. The iterator function returns the empty list once it has
    exhausted the files contained.

    The second argument can be a hash reference with options, which are
    identical to the arguments passed to "read()".

    Example usage:

        my $next = Archive::Tar->iter( "example.tar.gz", 1, {filter => qr/\.pm$/} );

        while( my $f = $next->() ) {
            print $f->name, "\n";

            $f->extract or warn "Extraction failed";

            # ....
        }

  Archive::Tar->list_archive($file, $compressed, [\@properties])
    Returns a list of the names of all the files in the archive. The first
    argument can either be the name of the tar file to list or a reference
    to an open file handle (e.g. a GLOB reference).

    If "list_archive()" is passed an array reference as its third argument
    it returns a list of hash references containing the requested properties
    of each file. The following list of properties is supported: full_path,
    name, size, mtime (last modified date), mode, uid, gid, linkname, uname,
    gname, devmajor, devminor, prefix, type.

    See "Archive::Tar::File" for details about supported properties.

    Passing an array reference containing only one element, 'name', is
    special cased to return a list of names rather than a list of hash
    references.

  Archive::Tar->extract_archive($file, $compressed)
    Extracts the contents of the tar file. The first argument can either be
    the name of the tar file to create or a reference to an open file handle
    (e.g. a GLOB reference). All relative paths in the tar file will be
    created underneath the current working directory.

    "extract_archive" will return a list of files it extracted. If the
    archive extraction fails for any reason, "extract_archive" will return
    false. Please use the "error" method to find the cause of the failure.

  $bool = Archive::Tar->has_io_string
    Returns true if we currently have "IO::String" support loaded.

    Either "IO::String" or "perlio" support is needed to support writing
    stringified archives. Currently, "perlio" is the preferred method, if
    available.

    See the "GLOBAL VARIABLES" section to see how to change this preference.

  $bool = Archive::Tar->has_perlio
    Returns true if we currently have "perlio" support loaded.

    This requires "perl-5.8" or higher, compiled with "perlio"

    Either "IO::String" or "perlio" support is needed to support writing
    stringified archives. Currently, "perlio" is the preferred method, if
    available.

    See the "GLOBAL VARIABLES" section to see how to change this preference.

  $bool = Archive::Tar->has_zlib_support
    Returns true if "Archive::Tar" can extract "zlib" compressed archives

  $bool = Archive::Tar->has_bzip2_support
    Returns true if "Archive::Tar" can extract "bzip2" compressed archives

  $bool = Archive::Tar->has_xz_support
    Returns true if "Archive::Tar" can extract "xz" compressed archives

  Archive::Tar->can_handle_compressed_files
    A simple checking routine, which will return true if "Archive::Tar" is
    able to uncompress compressed archives on the fly with "IO::Zlib",
    "IO::Compress::Bzip2" and "IO::Compress::Xz" or false if not both are
    installed.

    You can use this as a shortcut to determine whether "Archive::Tar" will
    do what you think before passing compressed archives to its "read"
    method.

GLOBAL VARIABLES
  $Archive::Tar::FOLLOW_SYMLINK
    Set this variable to 1 to make "Archive::Tar" effectively make a copy of
    the file when extracting. Default is 0, which means the symlink stays
    intact. Of course, you will have to pack the file linked to as well.

    This option is checked when you write out the tarfile using "write" or
    "create_archive".

    This works just like "/bin/tar"'s "-h" option.

  $Archive::Tar::CHOWN
    By default, "Archive::Tar" will try to "chown" your files if it is able
    to. In some cases, this may not be desired. In that case, set this
    variable to 0 to disable "chown"-ing, even if it were possible.

    The default is 1.

  $Archive::Tar::CHMOD
    By default, "Archive::Tar" will try to "chmod" your files to whatever
    mode was specified for the particular file in the archive. In some
    cases, this may not be desired. In that case, set this variable to 0 to
    disable "chmod"-ing.

    The default is 1.

  $Archive::Tar::SAME_PERMISSIONS
    When, $Archive::Tar::CHMOD is enabled, this setting controls whether the
    permissions on files from the archive are used without modification of
    if they are filtered by removing any setid bits and applying the current
    umask.

    The default is 1 for the root user and 0 for normal users.

  $Archive::Tar::DO_NOT_USE_PREFIX
    By default, "Archive::Tar" will try to put paths that are over 100
    characters in the "prefix" field of your tar header, as defined per
    POSIX-standard. However, some (older) tar programs do not implement this
    spec. To retain compatibility with these older or non-POSIX compliant
    versions, you can set the $DO_NOT_USE_PREFIX variable to a true value,
    and "Archive::Tar" will use an alternate way of dealing with paths over
    100 characters by using the "GNU Extended Header" feature.

    Note that clients who do not support the "GNU Extended Header" feature
    will not be able to read these archives. Such clients include tars on
    "Solaris", "Irix" and "AIX".

    The default is 0.

  $Archive::Tar::DEBUG
    Set this variable to 1 to always get the "Carp::longmess" output of the
    warnings, instead of the regular "carp". This is the same message you
    would get by doing:

        $tar->error(1);

    Defaults to 0.

  $Archive::Tar::WARN
    Set this variable to 0 if you do not want any warnings printed.
    Personally I recommend against doing this, but people asked for the
    option. Also, be advised that this is of course not threadsafe.

    Defaults to 1.

  $Archive::Tar::error
    Holds the last reported error. Kept for historical reasons, but its use
    is very much discouraged. Use the "error()" method instead:

        warn $tar->error unless $tar->extract;

    Note that in older versions of this module, the "error()" method would
    return an effectively global value even when called an instance method
    as above. This has since been fixed, and multiple instances of
    "Archive::Tar" now have separate error strings.

  $Archive::Tar::INSECURE_EXTRACT_MODE
    This variable indicates whether "Archive::Tar" should allow files to be
    extracted outside their current working directory.

    Allowing this could have security implications, as a malicious tar
    archive could alter or replace any file the extracting user has
    permissions to. Therefor, the default is to not allow insecure
    extractions.

    If you trust the archive, or have other reasons to allow the archive to
    write files outside your current working directory, set this variable to
    "true".

    Note that this is a backwards incompatible change from version 1.36 and
    before.

  $Archive::Tar::HAS_PERLIO
    This variable holds a boolean indicating if we currently have "perlio"
    support loaded. This will be enabled for any perl greater than 5.8
    compiled with "perlio".

    If you feel strongly about disabling it, set this variable to "false".
    Note that you will then need "IO::String" installed to support writing
    stringified archives.

    Don't change this variable unless you really know what you're doing.

  $Archive::Tar::HAS_IO_STRING
    This variable holds a boolean indicating if we currently have
    "IO::String" support loaded. This will be enabled for any perl that has
    a loadable "IO::String" module.

    If you feel strongly about disabling it, set this variable to "false".
    Note that you will then need "perlio" support from your perl to be able
    to write stringified archives.

    Don't change this variable unless you really know what you're doing.

  $Archive::Tar::ZERO_PAD_NUMBERS
    This variable holds a boolean indicating if we will create zero padded
    numbers for "size", "mtime" and "checksum". The default is 0, indicating
    that we will create space padded numbers. Added for compatibility with
    "busybox" implementations.

  Tuning the way RESOLVE_SYMLINK will works
            You can tune the behaviour by setting the $Archive::Tar::RESOLVE_SYMLINK variable,
            or $ENV{PERL5_AT_RESOLVE_SYMLINK} before loading the module Archive::Tar.

      Values can be one of the following:

                    none
               Disable this mechanism and failed as it was in previous version (<1.88)

                    speed (default)
               If you prefer speed
               this will read again the whole archive using read() so all entries
               will be available

        memory
               If you prefer memory

            Limitation

                    It won't work for terminal, pipe or sockets or every non seekable source.

FAQ
    What's the minimum perl version required to run Archive::Tar?
        You will need perl version 5.005_03 or newer.

    Isn't Archive::Tar slow?
        Yes it is. It's pure perl, so it's a lot slower then your "/bin/tar"
        However, it's very portable. If speed is an issue, consider using
        "/bin/tar" instead.

    Isn't Archive::Tar heavier on memory than /bin/tar?
        Yes it is, see previous answer. Since "Compress::Zlib" and therefore
        "IO::Zlib" doesn't support "seek" on their filehandles, there is
        little choice but to read the archive into memory. This is ok if you
        want to do in-memory manipulation of the archive.

        If you just want to extract, use the "extract_archive" class method
        instead. It will optimize and write to disk immediately.

        Another option is to use the "iter" class method to iterate over the
        files in the tarball without reading them all in memory at once.

    Can you lazy-load data instead?
        In some cases, yes. You can use the "iter" class method to iterate
        over the files in the tarball without reading them all in memory at
        once.

    How much memory will an X kb tar file need?
        Probably more than X kb, since it will all be read into memory. If
        this is a problem, and you don't need to do in memory manipulation
        of the archive, consider using the "iter" class method, or
        "/bin/tar" instead.

    What do you do with unsupported filetypes in an archive?
        "Unix" has a few filetypes that aren't supported on other platforms,
        like "Win32". If we encounter a "hardlink" or "symlink" we'll just
        try to make a copy of the original file, rather than throwing an
        error.

        This does require you to read the entire archive in to memory first,
        since otherwise we wouldn't know what data to fill the copy with.
        (This means that you cannot use the class methods, including "iter"
        on archives that have incompatible filetypes and still expect things
        to work).

        For other filetypes, like "chardevs" and "blockdevs" we'll warn that
        the extraction of this particular item didn't work.

    I'm using WinZip, or some other non-POSIX client, and files are not
    being extracted properly!
        By default, "Archive::Tar" is in a completely POSIX-compatible mode,
        which uses the POSIX-specification of "tar" to store files. For
        paths greater than 100 characters, this is done using the "POSIX
        header prefix". Non-POSIX-compatible clients may not support this
        part of the specification, and may only support the "GNU Extended
        Header" functionality. To facilitate those clients, you can set the
        $Archive::Tar::DO_NOT_USE_PREFIX variable to "true". See the "GLOBAL
        VARIABLES" section for details on this variable.

        Note that GNU tar earlier than version 1.14 does not cope well with
        the "POSIX header prefix". If you use such a version, consider
        setting the $Archive::Tar::DO_NOT_USE_PREFIX variable to "true".

    How do I extract only files that have property X from an archive?
        Sometimes, you might not wish to extract a complete archive, just
        the files that are relevant to you, based on some criteria.

        You can do this by filtering a list of "Archive::Tar::File" objects
        based on your criteria. For example, to extract only files that have
        the string "foo" in their title, you would use:

            $tar->extract(
                grep { $_->full_path =~ /foo/ } $tar->get_files
            );

        This way, you can filter on any attribute of the files in the
        archive. Consult the "Archive::Tar::File" documentation on how to
        use these objects.

    How do I access .tar.Z files?
        The "Archive::Tar" module can optionally use "Compress::Zlib" (via
        the "IO::Zlib" module) to access tar files that have been compressed
        with "gzip". Unfortunately tar files compressed with the Unix
        "compress" utility cannot be read by "Compress::Zlib" and so cannot
        be directly accesses by "Archive::Tar".

        If the "uncompress" or "gunzip" programs are available, you can use
        one of these workarounds to read ".tar.Z" files from "Archive::Tar"

        Firstly with "uncompress"

            use Archive::Tar;

            open F, "uncompress -c $filename |";
            my $tar = Archive::Tar->new(*F);
            ...

        and this with "gunzip"

            use Archive::Tar;

            open F, "gunzip -c $filename |";
            my $tar = Archive::Tar->new(*F);
            ...

        Similarly, if the "compress" program is available, you can use this
        to write a ".tar.Z" file

            use Archive::Tar;
            use IO::File;

            my $fh = IO::File->new( "| compress -c >$filename" );
            my $tar = Archive::Tar->new();
            ...
            $tar->write($fh);
            $fh->close ;

    How do I handle Unicode strings?
        "Archive::Tar" uses byte semantics for any files it reads from or
        writes to disk. This is not a problem if you only deal with files
        and never look at their content or work solely with byte strings.
        But if you use Unicode strings with character semantics, some
        additional steps need to be taken.

        For example, if you add a Unicode string like

            # Problem
            $tar->add_data('file.txt', "Euro: \x{20AC}");

        then there will be a problem later when the tarfile gets written out
        to disk via "$tar->write()":

            Wide character in print at .../Archive/Tar.pm line 1014.

        The data was added as a Unicode string and when writing it out to
        disk, the ":utf8" line discipline wasn't set by "Archive::Tar", so
        Perl tried to convert the string to ISO-8859 and failed. The written
        file now contains garbage.

        For this reason, Unicode strings need to be converted to
        UTF-8-encoded bytestrings before they are handed off to
        "add_data()":

            use Encode;
            my $data = "Accented character: \x{20AC}";
            $data = encode('utf8', $data);

            $tar->add_data('file.txt', $data);

        A opposite problem occurs if you extract a UTF8-encoded file from a
        tarball. Using "get_content()" on the "Archive::Tar::File" object
        will return its content as a bytestring, not as a Unicode string.

        If you want it to be a Unicode string (because you want character
        semantics with operations like regular expression matching), you
        need to decode the UTF8-encoded content and have Perl convert it
        into a Unicode string:

            use Encode;
            my $data = $tar->get_content();

            # Make it a Unicode string
            $data = decode('utf8', $data);

        There is no easy way to provide this functionality in
        "Archive::Tar", because a tarball can contain many files, and each
        of which could be encoded in a different way.

CAVEATS
    The AIX tar does not fill all unused space in the tar archive with 0x00.
    This sometimes leads to warning messages from "Archive::Tar".

      Invalid header block at offset nnn

    A fix for that problem is scheduled to be released in the following
    levels of AIX, all of which should be coming out in the 4th quarter of
    2009:

     AIX 5.3 TL7 SP10
     AIX 5.3 TL8 SP8
     AIX 5.3 TL9 SP5
     AIX 5.3 TL10 SP2

     AIX 6.1 TL0 SP11
     AIX 6.1 TL1 SP7
     AIX 6.1 TL2 SP6
     AIX 6.1 TL3 SP3

    The IBM APAR number for this problem is IZ50240 (Reported component ID:
    5765G0300 / AIX 5.3). It is possible to get an ifix for that problem. If
    you need an ifix please contact your local IBM AIX support.

TODO
    Check if passed in handles are open for read/write
        Currently I don't know of any portable pure perl way to do this.
        Suggestions welcome.

    Allow archives to be passed in as string
        Currently, we only allow opened filehandles or filenames, but not
        strings. The internals would need some reworking to facilitate
        stringified archives.

    Facilitate processing an opened filehandle of a compressed archive
        Currently, we only support this if the filehandle is an IO::Zlib
        object. Environments, like apache, will present you with an opened
        filehandle to an uploaded file, which might be a compressed archive.

SEE ALSO
    The GNU tar specification
        "http://www.gnu.org/software/tar/manual/tar.html"

    The PAX format specification
        The specification which tar derives from; "
        http://www.opengroup.org/onlinepubs/007904975/utilities/pax.html"

    A comparison of GNU and POSIX tar standards;
    "http://www.delorie.com/gnu/docs/tar/tar_114.html"
    GNU tar intends to switch to POSIX compatibility
        GNU Tar authors have expressed their intention to become completely
        POSIX-compatible;
        "http://www.gnu.org/software/tar/manual/html_node/Formats.html"

    A Comparison between various tar implementations
        Lists known issues and incompatibilities;
        "http://gd.tuwien.ac.at/utils/archivers/star/README.otherbugs"

AUTHOR
    This module by Jos Boumans <kane AT cpan.org>.

    Please reports bugs to <bug-archive-tar AT rt.org>.

ACKNOWLEDGEMENTS
    Thanks to Sean Burke, Chris Nandor, Chip Salzenberg, Tim Heaney, Gisle
    Aas, Rainer Tammer and especially Andrew Savige for their help and
    suggestions.

COPYRIGHT
    This module is copyright (c) 2002 - 2009 Jos Boumans <kane AT cpan.org>.
    All rights reserved.

    This library is free software; you may redistribute and/or modify it
    under the same terms as Perl itself.


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