Shell脚本初步学习

文章由LinuxBoy分享于2019-03-24 07:03:02热评（473）

Shell脚本初步学习

Shell脚本对于Linux下的系统管理员和运维的人来说很重要。最近看了一下Shell脚本，为了系统地学习一下Shell脚本，我看了一下《鸟哥的Linux私房菜基础学习篇》第三版，其中的第13章讲了一下Shell script的学习。

编写shell script的良好习惯

1、script的功能；

2、script的版本信息；

3、script的作者与联络方式；

4、script的版本声明方式；

5、script的History （历史记录)

6、script内较特殊的命令，使用“绝对路径”的方式来执行；

7、script执行时需要的环境变量预先声明和设置。

sh01.sh

[plain]

#!/bin/bash

# program:

# This program show "Hello World!" in your screen

# History:

# 2013/04/21 15:31 ccf First release

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin

export PATH

echo -e "Hello World! \a \n"

exit 0

sh02.sh

[plain]

#!/bin/bash

# Program

# User inputs his first name and last name. Program shows his full name.

# History

# 2013/04/21,by ccf,First release

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin

export PATH

read -p "Please input your first name: " firstname # 提示用户输入

read -p "Please input your last name: " lastname # 提示用户输入

echo -e "\nYour full name is: $firstname $lastname" #结果由屏幕输出

sh03.sh

[plain]

#!/bin/bash

# Program

# Program creates three files, which named by user's input

# and date command

# History:

# 2013/04/21 Sunday ccf First release

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/loacl/sbin:~/bin

export PATH

# 1.让用户输入文件名，并取得fileuser这个变量

echo -e "I will use 'touch' command to create 3 files." # 纯粹显示信息

read -p "Please input your filename: " fileuser # 提示用户输入

# 2.为了避免用户随意按【Enter】,利用变量功能分析文件名是否有设置

filename=${fileuser:-"filename"} # 开始判断是否有配置文件名

# 3.开始利用date命令来取得所需要的文件名了

date1=$(date --date='2 days ago' +%Y%m%d) # 前两天的日期

date2=$(date --date='1 days ago' +%Y%m%d) # 前一天的日期

date3=$(date +%Y%m%d) # 今天的日期

file1=${filename}${date1} # 下面三行在配置文件名

file2=${filename}${date2}

file3=${filename}${date3}

# 4.创建文件名

touch "$file1"

touch "$file2"

touch "$file3"

sh04.sh

[plain]

#!/bin/bash

# Program:

# User inputs 2 integer numbers; program will cross these two numbers.

# History:

# 2013/04/21 ccf19881030 First release

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin

export PATH

echo -e "You should input 2 numbers, I will cross them!\n"

read -p "first number: " firstnum

read -p "second number: " secondnum

total=$(($firstnum * $secondnum))

echo -e "\nThe result of $firstnum * $secondnum is ==> $total"

sh05.sh

[plain]

#!/bin/bash

#program:

# User input a filename, program will check the follwing:

# 1.) exist? 2.) file/directory? 3.) file permissions

#History:

# 2013/05/14 ccf First Release

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin

export PATH

#1、让用户输入文件名,并且判断用户是否真的有输入字符串

echo -e "Please input a filename, I will check the filename's type and permission. \n\n" #纯粹显示信息

read -p "Input a filename : " filename #提示用户输入

test -z $filename && echo "You MUST input a filename." && exit 0

#2、判断文件是否存在，若不存在则显示信息并结束脚本

test ! -e $filename && echo "The filename '$filename' DO NOT exist" && exit 0

#3、开始判断文件类型和属性

test -f $filename && filetype="regular file"

test -d $filename && filetype="directory"

test -r $filename && perm="readable"

test -w $filename && perm="$perm writeable"

test -x $filename && perm="$perm executable"

#4、开始输出信息！

echo "The filename: $filename is a $filetype"

echo "And the permission are : $perm"

sh06.sh

[plain]

#!/bin/bash

# Program:

# This program shows the user's choice

# History:

# 2013/05/14 ccf First release

PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin

export PATH

read -p "Please input (Y/N) : " yn

[ "$yn" == "Y" -o "$yn" == "y" ] && echo "OK, continue" && exit 0

[ "$yn" == "N" -o "$yn" == "n" ] && echo "Oh, interrupt!" && exit 0

echo "I don't know what your choice is" && exit 0

可以通过sh sh01.sh或者chmod a+x sh01.sh;./sh01.sh来执行shell脚本。

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