shell脚本编程100例

这里提供一些常见的Shell脚本编程案例，供参考：

1. 输出“Hello World!”

#!/bin/bash
echo "Hello World!"

2. 求两个数之和

#!/bin/bash
echo "Please enter the first number:"
read num1
echo "Please enter the second number:"
read num2
sum=$(($num1 + $num2))
echo "The sum of $num1 and $num2 is $sum"

3. 循环输出数字

#!/bin/bash
echo "Please enter a number:"
read num
for ((i=1;i<=num;i++))
do
echo $i
done

4. 判断一个数是否为偶数

#!/bin/bash
echo "Please enter a number:"
read num
if [ $((num%2)) -eq 0 ]
then
echo "$num is an even number"
else
echo "$num is an odd number"
fi

5. 判断一个文件是否存在

#!/bin/bash
echo "Please enter the file name:"
read filename
if [ -e $filename ]
then
echo "$filename exists"
else
echo "$filename does not exist"
fi

6. 输出当前日期和时间

#!/bin/bash
echo "The current date and time is $(date)"

7. 输出当前用户的用户名和主目录

#!/bin/bash
echo "The current user is $(whoami)"
echo "The home directory for the current user is $HOME"

8. 拷贝一个文件到另一个目录

#!/bin/bash
echo "Please enter the file name:"
read filename
echo "Please enter the destination directory:"
read destdir
cp $filename $destdir
echo "File $filename copied to $destdir"

9. 列出当前目录下的所有文件

#!/bin/bash
echo "Files in the current directory:"
ls

10. 判断一个字符串是否为空

#!/bin/bash
echo "Please enter a string:"
read str
if [ -z $str ]
then
echo "The string is empty"
else
echo "The string is not empty"
fi

希望这些例子能够帮助您更好地了解Shell脚本编程。