#!/bin/bash

if [ $# -le  ] ; then

        echo "prase is wrong ,please check first"

        exit

fi
#知识点：
　　1，$#代表了命令行的参数数量
　　2，-le表示小于等于，拓展 lt表示小于，gt表示大于，ge表示大于等于，eq表示等于，ne表示不等于

if [ "$1"x != "online"x ] && [ "$1"x != "neibu"x ] ; then

        echo "you must input online or neibu !"

        exit

fi

#知识点：
　　1，注意到"$1"x最后的x，这是特意安排的，因为当$1为空的时候，上面的表达式就变成了x = onlinex，显然是不相等的。而如果没有这个x，表达式就会报错：[: =: unary operator expected
　　2，注意到等号两边各有一个空格
　　3，&&符号链接

if [ "$1"x = "online"x ] ; then

        case $ in

                pm)

                        mysql -h xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;;

                admin)

                        mysql -h xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;;

        esac

elif [ "$1"x = "neibu"x ] ; then

        case $ in

                pm)

                        mysql -h xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;;

                admin)

                        mysql -h xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx ;;

        esac

fi

知识点：
　　case语法

　　ase ... in

   　　...) do something here

   　　;;

　　esac

#!/bin/bash  

case "$1" in

    start)

        echo "mysql start..."

        /etc/init.d/mysqld start

        ;;

    stop)

        echo "mysql stop..."

        /etc/init.d/mysqld stop

        ;;

    restart)

        echo "mysql restart..."

        /etc/init.d/mysqld stop

        /etc/init.d/mysqld start

        ;;

esac  

exit