#!/bin/bash
echo '==== test output ====='
echo $0
echo $1
echo $2
echo $3
echo $#
echo $*
echo $@

# case
echo '========================'
echo 'Please input two numbers:'
read a b
for arg in $*; do
  case $arg in
    add)
      echo $[a+b]
      ;;
    substract)
      echo $[a-b]
      ;;
    multiply)
      echo $[a*b]
      ;;
    *)
      exit
      ;;
  esac
done

