timesave extract process

extract.sh

#!/bin/bash
                                                                                              
extract() {                                                                                   
    if [[ -z "$1" ]]; then                                                                    
        echo "Usage: extract <file>.<zip|rar|bz2|gz|tar|tbz2|tgz|Z|7z|xz|ex|tar.bz2|tar.gz|tar.xz>"                                                                                         
        exit 1                                                                                
    else                                                                                      
        if [[ -f "$1" ]]; then
            case $1 in
                *.7z) 7z x $1;;
                *.tar.bz2) tar xvjf $1;;
                *.tar.gz) tar xvzf $1;;
                *.bz2) bunzip2 $1;;
                *.gz) gunzip $1;;
                *.tar.xz) tar xvJf $1;;
                *.tar) tar xvf $1;;
                *.tbz2) tar xvjf $1;;
                *.tgz) tar xvzf $1;;
                *.Z) uncompress $1;;
                *.xz) unxz $1;;
                *.lzma) unlzma $1;;
                *.rar) unrar x -ad $1;;
                *.zip) unzip $1;; 
                *) echo "extract: '$1' - unknown archive method"; exit 1;;
            esac
        else
            echo "$1 - file not found"
            exit 1
        fi
    fi
}
extract $1