Linux Smart 解压文件

#!/bin/bash
# 概要文件类型自动解压
ftype=`file "$1"`
case "$ftype" in
    "$1: Zip archive"*)
        if [ -z "$2" ]; then
            unzip "$1"
        else
            unzip "$1" -d "$2"
        fi
        ;;
    "$1: gzip compressed"*)
        if [ -z "$2" ]; then
            tar -zxvf "$1"
        else
            tar -zxvf "$1" -C "$2"
        fi
        ;;
    "$1: bzip2 compressed"*)
        if [ -z "$2" ]; then
            tar -jxvf "$1"
        else
            tar -jxvf "$1" -C "$2"
        fi
        ;;
    *) echo "File $1 can not be uncompressed with smartzip";;
esac