SECTION=$(expr $OPTARG - 1 2>/dev/null) if [[ $? == 2 ]]; then echo "secion number is invalid. exit." exit 2 fi も let SECTION="OPTARG - 1" 2>/dev/null case $SECTION in [0-7]) :;; *) echo "secion number is invalid. exit." exit 1;; esac で外部コマンドはサヨウナラ
if [[ ( ! -e "$COMMAND" ) || ( ! -x "$COMMAND" ) ]]; then は if [[ ! -x "$COMMAND" ]]; then で十分だと思うが