17、Shell编程应用

17、Shell编程应用

命令替换
echo 'date' 输出date命令结果
echo "The date is 'date'"

Example 1

echo "the date is 'date'"

expr  4 + 5 ##算数展开，有空格

echo $((4+5)) ##有无空格都可以

Example 2 CallCenter

#!/bin/bash

echo "Please enter Total number:"
read totalNumber
echo "Please enter resolve number:"
read resNunber

echo $((totalNumber-resNumber))

Example 3 Avg.sh

echo "Please enter score:"
read score

if test $score -lt 80
then
    echo "Bad!!!"
elif test $score -ge 80 -a $score -lt 90
then
    echo "Good!!"
else
    echo "Very Good!!"
fi

vi编译器 set nu 显示行号