一定時間後にベルを鳴らす(タイマー)

#!/bin/sh
#call.sh

echo " 1) 3 minutes"
echo " 2) 4 minutes"
echo " 3) 5 minutes"
echo " 4) End Menu"

echo -n " Select Number: "

while read ANSWER; do
    case "${ANSWER}" in
        1) sleep 3m
            echo -e \\a ; sleep 1s ;
            echo -e \\a ; sleep 1s ;
            echo -e \\a ; break ;;
        2) sleep 4m
            echo -e \\a ; sleep 1s ;
            echo -e \\a ; sleep 1s ;
            echo -e \\a ; break ;;
        3) sleep 5m
            echo -e \\a ; sleep 1s ;
            echo -e \\a ; sleep 1s ;
            echo -e \\a ; break ;;
        4) echo "*** Menu End. ***" ; break ;;
        *) echo "*** Menu not found. ***" ;;
    esac
    echo -n " Select Number: "
done
unset ANSWER