case用法

echo "a is 5, b is 3. Please select you method"
a=5
b=3
select c in "a+b" "a-b" "a*b" "a/b"; do
  break
done

case $c in
"a+b") echo "$a+$b"= ` expr $a + $b `;;
"a-b") echo "$a-$b"= ` expr $a - $b `;;
"a*b") echo "$a*$b"= ` expr $a \* $b `;;
"a/b") echo "$a/$b"= ` expr $a / $b `;;
*) echo "other"
esac