shell实现一个简单的计算器功能小脚本
#!/bin/bash# author by alsww
# date : 2016.02.03
# mail : alsww@qq.com
# blog : alsww.blog.51cto.com
print_info(){
printf "请输入数字:\n"
}
print_err_num(){
printf "请输入正确的数字!\n"
}
print_err_fuhao(){
printf "请输入正确的运算符号(+ - * /):\n"
}
while :
do
read -p "请输入第一个数字:" num1
echo $num1|grep -q '^[-]\?\+$' && break || print_err_num
done
while :
do
read -p "请输入一个运算符（形如 ：+ - * /）:" ysf
[ "$ysf" != "+" ]&&[ "$ysf" != "-" ]&&[ "$ysf" != "*" ]&&[ "$ysf" != "/" ] && print_err_fuhao || break
done
while :
do
read -p "请输入第二个数字:" num2
echo $num2|grep -q '^[-]\?\+$' && break || print_err_num
done
echo "运算结果为：${num1}${ysf}${num2}=$((${num1}${ysf}${num2})) "
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