shell script 入门

在 shell script 注意必须使用完全相同写在下面：

1.  指令的运行是从上而下、从左而右的分析与运行；

2.  指令的运行就如同第五章内提到的： 指令、选项不參数间的多个空白都会被忽略掉；

3.  空白行也将被忽略掉，并且 [tab] 按键所推开的空白相同规为空格键；

4.  假设读取到一个 Enter 符号 (CR) 。就尝试開始运行该行 (或该串) 命令；


5.  至亍假设一行的内容太多，则能够使用『 \[Enter] 』来延伸至下一行。

6.  『 # 』可做为批注。不论什么加在 # 后面的资料将所有被规为批注文字而被忽略。

第一个shell script。必须是hello world。哈哈

#!/bin/bash

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

export PATH

echo -e  "hello world!  \n"

exit 0

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh01.sh

hello world!

特此说明一下，Ubuntu默认的shell是dash，而不是bash。echo -e时候会有问题。会把-e也打印出来。



转载link：http://webnoties.blog.163.com/blog/static/1835251412013518362635/

非常谢谢作者的blog帮我搞定了这个默认shell不是bash的问题

由于ubuntu默认的sh是连接到dash的,又由于dash跟bash的不兼容所以出错了.运行时能够把sh换成bash 文件名称.sh来运行.成功.dash是什么东西,查了一下,应该也是一种shell,貌似用户对它的诟病颇多.

by the way改动sh默认连接到bash的一种方法：

sudo dpkg-reconfigure dash

选择no就可以.

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.29

# code file   : sh02.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program would ask the user to input some varible's value

#       and then print them out into the screen.

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

export PATH

read -p "Please input your first name:" first_name #give the user a message whatshould be inputed

read -p "Please input your second name" second_name

echo -e "\nYour full name is $first_name $second_name" #print out the user's name

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh02.sh

Please input your first name:Jason

Please input your second nameLeaster



Your full name is Jason Leaster

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.29

# code file   : sh04.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for demonstrating some

#       mathmatical operations on varibles which in bash script

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

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

read -p "first number: " first_num

read -p "second number: " second_num

total=$(($first_num*second_num))

echo -e "total is : $total"

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh04.sh

You SHOULD input 2 numbers ,I will cross them !



first number: 10

second number: 25

total is : 250





不怕丢人的说，上面这地方写成$(total)差点纠结而shi。。

。

。

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.29

# code file   : sh05.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for command -- test

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

echo -e "Please input a filename, I will check the filename's type and permission.\n\n"

read -p "Input a filename : " filename

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

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

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

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

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

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

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

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

echo "And the permissions are: $perm"

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh05.sh

Please input a filename, I will check the filename's type and permission.





Input a filename : sh01.sh

The filename: sh01.sh is a regulare file

And the permissions are: writable

删除一个环境变量用      unset 环境变量名

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.29

# code file   : sh06.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for [ A==B ]

#       If you find something wrong with my code, please touch me.

#       Thank you!

PATH=/bin/:/sbin/:/usr/sbin/:/usr/local/sbin/:/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 "NO,interrupt" && exit 0

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

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh06.sh

Please input (Y/N) : y

OK, continue

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.29

# code file   : sh07.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo that user input a file name

#       and some parameters, lately program process it and print out the file

#       type and permission.

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

echo "The script name is ==> $0"

echo "Total parameter numbe is ==> $#"

[ "$#" -lt 2 ] && echo "The number of parameter is less than 2. Stop here" && exit 0

echo "Your whole parameter is ==> $@"

echo "1st parameter ==> $1"

echo "2nd parameter ==> $2"

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh07.sh

The script name is ==> ./sh07.sh

Total parameter numbe is ==> 0

The number of parameter is less than 2. Stop here

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh07.sh hello world

The script name is ==> ./sh07.sh

Total parameter numbe is ==> 2

Your whole parameter is ==> hello world

1st parameter ==> hello

2nd parameter ==> world

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.30

# code file   : sh08.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for command -- shift

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

echo "Total parameter number is ==> $#"

echo "Your whole parameter is ==> $@"

shift

echo "Total parameter number is ==> $#"

echo "Your whole parameter is ==> $@"

shift 3

echo "Total parameter number is ==> $#"

echo "Your whole parameter is ==> $@"

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh08.sh

Total parameter number is ==> 0

Your whole parameter is ==>

Total parameter number is ==> 0

Your whole parameter is ==>

Total parameter number is ==> 0

Your whole parameter is ==>

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh08.sh hello world

Total parameter number is ==> 2

Your whole parameter is ==> hello world

Total parameter number is ==> 1

Your whole parameter is ==> world

Total parameter number is ==> 1

Your whole parameter is ==> world

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh08.sh hello world jason leaster tonight

Total parameter number is ==> 5

Your whole parameter is ==> hello world jason leaster tonight

Total parameter number is ==> 4

Your whole parameter is ==> world jason leaster tonight

Total parameter number is ==> 1

Your whole parameter is ==> tonight

有意思的是假设文件名称之后没有“參数”，parameter number就是0，假设參数少于shift移动的距离(例如说代码中的shift 3),就会保留最低数目为1，假设參数少于shift移动的距离

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.30

# code file   : sh08.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for "if[] ; then fi"

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

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

if [ "$yn" == "Y" -o "$yn" == "y" ]; then

        echo "OK,continue"

        exit 0

fi

if [ "$yn" == "N" -o "$yn" == "n" ]; then

        echo "Oh,interrupt!"

        exit 0

fi

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

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh09.sh

Please input (Y/N) :y

OK,continue

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh09.sh

Please input (Y/N) :n

Oh,interrupt!

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.30

# code file   : sh9.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for "if[] ; elif [] ;then else fi"

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

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

if [ "$yn" == "Y" -o "$yn" == "y" ]; then

        echo "OK,continue"

        exit 0

elif [ "$yn" == "N" -o "$yn" == "n" ];then

        echo "Oh,interrupt!"

        exit 0

else

        echo "Are you kidding me?

You don't know what means \"Input (Y/N)\" \n"

fi

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

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh10.sh

Please input (Y/N) :hehe

Are you kidding me? You don't know what means "Input (Y/N)" \n

I don't know what your choice is

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.30

# code file   : sh10.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for "if[] ; elif [] ;then else fi"

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

echo "This program will print your selection !"

case $1 in

        "one")

        echo "Your choice is ONE"

        ;;

        "two")

        echo "Your choice is TWO"

        ;;

        *)

        echo "42"

        ;;

esac

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh12.sh hello world

This program will print your selection !

42

#! /bin/bash

# code writer : EOF

# code date   : 2014.07.30

# code file   : sh13.sh

# e-mail      : jasonleaster@gmail.com

# code purpose:

#               This program was coded for a demo for "function and while loop"

#       If you find something wrong with my code, please touch me.

#       Thank you!

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

export PATH

function secret()

{

        echo "hello world!"

}

temp=10

while [  $temp != 0 ]

do

        secret

        temp=$(($temp-1))

        echo "$temp"

done

jasonleaster@ubuntu:~/shell_script_beginner$ sh ./sh13.sh

hello world!

9

hello world!

8

hello world!

7

hello world!

6

hello world!

5

hello world!

4

hello world!

3

hello world!

2

hello world!

1

hello world!

0

最后sh -x将使用do啊的script 内容显示到屏幕上，这是非常实用的參数，而-n不会显示不论什么信息

jasonleaster@ubuntu:~/shell_script_beginner$ sh -x ./sh13.sh

+ PATH=/bin/:/sbin/:/usr/sbin/:/usr/local/sbin/:/usr/local/sbin:/home/liuzjian/bin

+ export PATH

+ temp=2

+ '[' 2 '!=' 0 ']'

+ secret

+ echo 'hello world!'

hello world!

+ temp=1

+ echo 1

1

+ '[' 1 '!=' 0 ']'

+ secret

+ echo 'hello world!'

hello world!

+ temp=0

+ echo 0

0

+ '[' 0 '!=' 0 ']'

去衡山的时候，在白龙潭(应该是吧。不记得啦。。。

)遇见的两个小孩。。

。多么美好年纪啊。。。

版权声明：本文博客原创文章，博客，未经同意，不得转载。

shell script 入门 笔记的更多相关文章

  1. linux基础之Shell Script入门介绍

    本文介绍下,学习shell script编程的入门知识,通过几个入门实例,带领大家走进shell script的神圣殿堂,呵呵,有需要的朋友参考下. 本文转自:http://www.jbxue.com ...

  2. shell script入门

    从程序员的角度来看, Shell本身是一种用C语言编写的程序,从用户的角度来看,Shell是用户与Linux操作系统沟通的桥梁.用户既可以输入命令执行,又可以利用 Shell脚本编程,完成更加复杂的操 ...

  3. bash shell学习-shell script基础 (笔记)

    A chain no stronger than its weakest link. "一着不慎,满盘皆输" 参考资料:鸟哥的Linux私房菜 基础学习篇(第三版)  Linux ...

  4. Shell Script 入门教程

    和 Shell 的区别 Shell 是一个用 C 语言编写的程序,它是用户使用 Linux 的桥梁. Shell 即是一种命令语言,又是一种程序设计语言. Shell 是指一种应用程序,这个应用程序提 ...

  5. shell script简单笔记

    变量 shell script是一种脚本语言,变量的定义是通过 myName=HYB 这样的形式定义的. 当存在空格时,可以通过双引号或单引号将其变为字符串.双引号不进行转义,单引号将内容进行转义为一 ...

  6. shell script 学习笔记-----if,for,while,case语句

    1.if内的判断条件为逻辑运算: 2.if内的判断条件为目录是否存在,文件是否存在,下图先检验目录/home/monster是否存在,然后再检测/home/monster中的file.txt文件是否存 ...

  7. shell script 学习笔记-----shell变量

    1.在赋值语句name=value中不能存在空格,例如:name = value这样的形式会被认为是三个变量,因为本质上来说,脚本的内容就是传给shell程序的变量,而变量之间是通过空格区分的.如果想 ...

  8. shell script 学习笔记-----命令执行

    1.PATH变量:shell最主要的功能就是执行用户输入的命令,例如当用户输入一条“ls”命令之后,shell就要找到该命令对应的文件并执行.通常shell都会设置一个名叫PATH的环境变量,其中保存 ...

  9. shell script 学习笔记-----标准输出

    1.将标准输出(stdout)和标准错误输出(stderr)分别重定向到两个不同的文件 其中符号'>'默认将标准输出重定向,意思和'1>'相同,‘2>'表示重定向标准错误输出,数字1 ...

随机推荐

  1. JS数组追加数组採用push.apply的坑

    JS数组追加数组没有现成的函数,这么多年我已经习惯了a.push.apply(a, b);这样的自以为非常酷的,不须要写for循环的写法,一直也没遇到什么问题,直到今天我要append的b是个非常大的 ...

  2. thinkphp中field的用法

    ThinkPHP的连贯操作方法中field方法有很多的使用技巧,field方法主要目的是标识要返回或者操作的字段,下面详细道来. 1.用于查询 在查询操作中field方法是使用最频繁的. $Model ...

  3. C++——STL中三种顺序容器的简要差别

    C++ STL 提供了3个顺序容器 :vector, deque, list Vector动态数组.支持高速訪问:list双向链表,支持高速插入和删除. vector 中的元素是顺序存放的.所以随机訪 ...

  4. 采用Bash脚本性能监控过程

    为一个Linux过程监控,采用Bash脚本. 采用ps命令的过程监控,使用周期加上连续监测的睡眠时间. 使用方法: psmonitor.sh -p [pid] -d [interval] -n [st ...

  5. mysql主键设置成auto_increment时，进行并发性能測试出现主键反复Duplicate entry 'xxx' for key 'PRIMARY'

    mysql主键设置成auto_increment时,进行并发性能測试出现主键反复Duplicate entry 'xxx' for key 'PRIMARY' 解决方法: 在my.cnf的[mysql ...

  6. Oracle自增列创建方法

    最近在做Oracle的项目,由于以前没有接触过Oracle的开发,遇到了不少的问题,比如给Oracle表添加自增列,与SQL Server就不同. Oracle没有自增字段这样的功能,但是通过触发器( ...

  7. Hyper-V笔记

    Hyper-V的网络架设 Hyper-V中创建“虚拟网络”(可看成交换机)会在物理机中创建相应的虚拟网卡.Hyper-V安装好后会默认创建一个“本地连接-虚拟网络”对应的虚拟网卡给物理机使用,原本的本 ...

  8. JSP生成word文件

    1.jsp生成word文件,直接改动jsp格式: <%@ page contentType="application/vnd.ms-word;charset=GB2312"% ...

  9. java线程例子登山

    Through its implementation, this project will familiarize you with the creation and execution of thr ...

  10. centos6.5安装nodejs

    Preface(前言) 一次偶然的机会知道有nodejs这个东西,确实对它还是非常感兴趣的.刚開始仅仅知道它能让javascript写后台,然后前后台都由javascript来写,确实认为真的挺爽,毕 ...