原文：http://bash.cyberciti.biz/shell-math/sum-of-two-numbers-2/
以下是该shell脚本的源代码：
#!/bin/bash
# Script to display sum of two number and to do calculations such as +, -, / etc
# ----------------------------------------------------------------------
echo "**** My calculator ****"
echo "M A I N - M E N U"
echo "1. Multiplication"
echo "2. Subtraction"
echo "3. Remainder"
echo "4. Divide"
echo -n "Please select your choice (1-4) : "
read choice
echo -n "Enter your first number : "
read n1
echo -n "Enter your second number : "
read n2
if [ $choice -eq 1 ]
then
answer="$n1 x $n2 = $(( $n1 * $n2 ))"
elif [ $choice -eq 2 ]
then
answer="$n1 - $n2 = $(( $n1 - $n2 ))"
elif [ $choice -eq 3 ]
then
answer="$n1 % $n2 = $(( $n1 % $n2 ))"
elif [ $choice -eq 4 ]
then
answer="$n1 / $n2 = $(( $n1 / $n2 ))"
else
echo "Sorry please select number between 1-4 only"
exit 1
fi
echo $answer |