#!/bin/sh
#
# lz.sh, Copyright © 2010 Matteo Cypriani
#
# This program is free software. It comes without any warranty, to
# the extent permitted by applicable law. You can redistribute it
# and/or modify it under the terms of the Do What The Fuck You Want
# To Public License, Version 2, as published by Sam Hocevar. See
# http://sam.zoy.org/wtfpl/COPYING for more details.
#
# This script emulates and extends commands lz and uz from the mtools.
# It handles: .tar, .tar.gz, .tar.bz2, .tar.xz, .tar.lzma and .tar.Z,
# through the standards options of GNU tar.
# If the script name is "lz", the archive content is displayed. If the
# name is "uz", it is extracted.
# Note that you need GNU Tar, at least version 1.20 to support LZMA,
# and 1.22 to support XZ.


## Verify program name ##

PROGRAM="$(basename "$0")"

if [ "$PROGRAM" = "lz" ] ; then
    ACTION="t"
elif [ "$PROGRAM" = "uz" ] ; then
    ACTION="x"
else
    printf 'Error! Program name is "%s" (not "lz" nor "uz")!\n' "$PROGRAM" >&2
    exit 1
fi


## Verify number of arguments ##

if [ $# -lt 1 ] ; then
    echo "$PROGRAM requires at least one argument!" >&2
    exit 2
fi


## Process files ##

for F in "$@" ; do
    if [ "$ACTION" = "t" ] ; then
        echo "*** Listing « $F » ***" >&2
    else
        echo "Extracting « $F »…"
    fi

    # Simple Tar archive
    if [ "$(basename "$F" .tar)" != "$F" ] ; then
        FORMAT=""

    # GZipped Tar
    elif [ "$(basename "$F" .tar.gz)" != "$F" ] || \
         [ "$(basename "$F" .tgz)" != "$F" ] ; then
        FORMAT="--gzip"

    # BZipped Tar
    elif [ "$(basename "$F" .tar.bz2)" != "$F" ] || \
         [ "$(basename "$F" .tbz)" != "$F" ] || \
         [ "$(basename "$F" .tb2)" != "$F" ] ; then
        FORMAT="--bzip"

    # XZipped Tar
    elif [ "$(basename "$F" .tar.xz)" != "$F" ] || \
         [ "$(basename "$F" .txz)" != "$F" ] ; then
        FORMAT="--xz"

    # Compressed Tar
    elif [ "$(basename "$F" .tar.Z)" != "$F" ] || \
         [ "$(basename "$F" .taz)" != "$F" ] ; then
        FORMAT="--compress"

    # LZMA compressed Tar
    elif [ "$(basename "$F" .tar.lzma)" != "$F" ] || \
         [ "$(basename "$F" .tlz)" != "$F" ] ; then
        FORMAT="--lzma"

    # Unknown extension
    else
        printf 'Extension of file "%s" unknown! (skipping)\n' "$F" >&2
        continue
    fi

    tar "$FORMAT" -"$ACTION"f "$F"
done

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