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初识shell脚本

2018-08-14 09:54:28来源：博客园阅读 ()

1.1 脚本认识

1 #!/bin/bash

第一行，通常用来指定执行脚本的shell ,/bin/bash是CentOS 默认的shell 如果写到第二行，就是注释了

1 #!/bin/sh

这样写也是可以的，sh是bash的软链接，和#!/bin/bash 是没有区别的，理规范的开头使用#!/bin/bash

1.2 查看bash版本

 1 [root@oldboy-lesson scripts]# bash --version
 2 GNU bash, version 4.1.2(2)-release (x86_64-redhat-linux-gnu)
 3 Copyright (C) 2009 Free Software Foundation, Inc.
 4 License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
 5  
 6 This is free software; you are free to change and redistribute it.
 7 There is NO WARRANTY, to the extent permitted by law.
 8 [root@oldboy-lesson scripts]# cat test_1.sh
 9 #!/bin/bash
10 user=`whoami`
11 echo $user
12 [root@oldboy-lesson scripts]# sh test_1.sh
13 root
14 [root@oldboy-lesson scripts]# ./test_1.sh
15 root
16 [root@oldboy-lesson scripts]# . test_1.sh
17 root
18 [root@oldboy-lesson scripts]# source test_1.sh
19 root
20 [root@oldboy-lesson scripts]# /bin/bash test_1.sh
21 root
22 [root@oldboy-lesson scripts]# /bin/sh test_1.sh
23 root
24 [root@oldboy-lesson scripts]# /server/scripts/test_1.sh
25 root

1.3 书写脚本

1.3.1 执行脚本

1.3.1.1 小结：

执行脚本的方法有：sh ./ . source /bin/bash /bin/sh pwd/

1.4 继承脚本变量

 1 [root@oldboy-lesson scripts]# sh test_1.sh
 2 root
 3 [root@oldboy-lesson scripts]# echo $user
 4  
 5 [root@oldboy-lesson scripts]# ./test_1.sh
 6 root
 7 [root@oldboy-lesson scripts]# echo $user
 8  
 9 [root@oldboy-lesson scripts]# bash test_1.sh
10 root
11 [root@oldboy-lesson scripts]# echo $user
12  
13 [root@oldboy-lesson scripts]# . test_1.sh
14 root
15 [root@oldboy-lesson scripts]# echo $user
16 root
17 [root@oldboy-lesson scripts]# source test_1.sh
18 root
19 [root@oldboy-lesson scripts]# echo $user
20 root