function img2iso () {
  if [ -z "$1" ]; then
    # display usage if no parameters given
    echo "Usage: img2iso <file_name>"
    return 1
  else
    if [ -f "$1" ] ; then
      filename=`basename $1 .img`
      hdiutil convert ${filename}.img -format UDTO -o ${filename}.iso
      mv ${filename}.iso.cdr ${filename}.iso
    else
        echo "'$n' - file does not exist"
        return 1
    fi
  fi
}