vim a.sh
read -p "please input sz01:" -t 30 a
read -p "please input (+ - * /):" -t 30 b
read -p "pleade input sz02:" -t 30 c
sum=$(($a+$b+$c))
echo "$sum"
vim a.sh
read -p "please input sz01:" -t 30 a
read -p "please input (+ - * /):" -t 30 b
read -p "pleade input sz02:" -t 30 c
sum=$(($a+$b+$c))
echo "$sum"