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
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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
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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
1.4.1.1 小结
继承：source 和 . 能继承脚本的变量，其它命令皆不能继承