shell 脚本中的参数使用

一、应用场景

# /usr/bin/mysql -u root -p
# /usr/sbin/apachectl -k stop

脚本后面的数据，是如何传递到脚本中的呢？

二、关于【$#】【$@】【$*】 的使用

先看一组示意图

# /path/to/scriptname  opt1  opt2  opt3  opt4 
       $0               $1    $2    $3    $4

• 【$#】：表示参数的总数.
• 【$@】：$1、$2……$5，按顺序表示每一个参数.
• 【$*】：表示所有参数的名称.

举例说明

脚本：sh07.sh
#!/bin/bash
# Program
# test
# History
# 2015/03/31 woodie first release
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/usr/local/sbin:~/bin
export PATH

echo "The script name is ==>$0"
echo "Total parameter number is ==>$#"
[ "$#" -lt 2 ] && echo -e "The number of parameter is less than 2. Stop here."\
 && exit 0
echo "Your whole parameter is ==>$*"
echo "The 1st parameter ==>$1"
echo "The 2nd parameter ==>$2"

运行结果：
# sh sh07.sh aaa bbb ccc
The script name is          ==>sh07.sh
Total parameter number is   ==>3
Your whole parameter is     ==>aaa bbb ccc
The 1st parameter           ==>aaa
The 2nd parameter           ==>bbb

三、shift 参数偏移

举例说明用法：

脚本：sh08.sh
#!/bin/bash
# Program
# test
# History
# 2015/03/31 woodie first release
PATH=/bin:/sbin:/usr/bin:/usr/sbin:/usr/local/bin:/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 ==>$#"
echo "Your whole parameter is   ==>$*"
运行结果：
# sh sh08.sh aaa bbb ccc ddd eee fff
Total parameter number is ==>6
Your whole parameter is   ==>aaa bbb ccc ddd eee fff
Total parameter number is ==>5
Your whole parameter is   ==>bbb ccc ddd eee fff
Total parameter number is ==>2
Your whole parameter is   ==>eee fff