extract file in linux

extract () {
   if [ -f $1 ] ; then
       case $1 in
 *.tar.bz2) tar xvjf $1 && cd $(basename "$1" .tar.bz2) ;;
 *.tar.gz) tar xvzf $1 && cd $(basename "$1" .tar.gz) ;;
 *.tar.xz) tar Jxvf $1 && cd $(basename "$1" .tar.xz) ;;
 *.bz2)  bunzip2 $1 && cd $(basename "$1" /bz2) ;;
 *.rar)  unrar x $1 && cd $(basename "$1" .rar) ;;
 *.gz)  gunzip $1 && cd $(basename "$1" .gz) ;;
 *.tar)  tar xvf $1 && cd $(basename "$1" .tar) ;;
 *.tbz2)  tar xvjf $1 && cd $(basename "$1" .tbz2) ;;
 *.tgz)  tar xvzf $1 && cd $(basename "$1" .tgz) ;;
 *.zip)  unzip $1 && cd $(basename "$1" .zip) ;;
 *.Z)  uncompress $1 && cd $(basename "$1" .Z) ;;
 *.7z)  7z x $1 && cd $(basename "$1" .7z) ;;
 *)  echo "don't know how to extract '$1'..." ;;
       esac
   else
       echo "'$1' is not a valid file!"
   fi
}

http://ubuntuforums.org/showthread.php?t=1116012