记录 shell学习过程（8）函数

 start () {

       echo "Apache start ......        [OK]"
       #return 0   可以写一个返回值，比如执行成功返回 0
 }

 stop () {

       echo "Apache stop ......        [Fail]"
 }

 start    #调用函数 直接写函数名即可
 stop

实战 nginx 启动管理脚本

 #!/usr/bin/env bash

 nginx_dir=/usr/local/nginx
 nginxd=$nginx_dir/sbin/nginx
 pid_file=$nginx_dir/logs/nginx.pid
 proc=nginx

 if [ -e $pid_file ];then

     nginx_process_id=`cat $pid_file`
     nginx_process_num=`ps aux | grep $nginx_process_id | grep -v "grep" | wc -l`
 fi
 start(){

 if [ ! -e /etc/init.d/network ];then

         echo' /etc/init.d/network doesn`t exist'
         exit
 fi
 . /etc/init.d/functions

 if [ -e $pid_file ] && [ $nginx_process_num -ge  ];then
     echo "nginx running..."
 else
    if [ -e $pid_file ] && [ $nginx_process_num -lt  ];then
         rm -f $pid_file
        echo " nginx start  ` daemon $nginxad` "
        #action "nginx start " $nginxd    另外一种写法 对应27行
    fi
 echo " nginx start  ` daemon $nginxd` "

 fi

 }
 stop(){

 if [ -e $pid_file ] && [ $nginx_process_num -ge  ];then

         echo "  nginx stop `killall -s QUIT $proc`"
 else
         echo 'nginx stop error'
 fi
 }

 restart(){
   stop
   sleep
   start
 }

 reload(){

 if [ -e $pid_file ] && [ $nginx_process_num -ge  ];then
    echo "nginx reload `killall -s HUP $proc`"
 else
    echo 'nginx reload failed'

 fi
 }
 status(){
 if [ -e $pid_file ] && [ $nginx_process_num -ge  ];then

   echo 'nginx running'
 else
   echo 'nginx stop'
 fi

 }

 case $ in
 start) start;;
 stop) stop;;
 restart) restart;;
 reload) reload;;
 status) status;;
 *) echo "USAGE: $0 start|stop|restart|reload|status" ;;
 esac

然后将脚本复制到 /etc/init.d/中并命名为nginxd

再修改权限chmod 755 /etc/init.d/nginxd

然后就可以通过service来个控制了

service nginxd status
nginx running