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 1 ];then
    echo "nginx running..."
else
   if [ -e $pid_file ] && [ $nginx_process_num -lt 1 ];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 1 ];then

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

restart(){
  stop
  sleep 3
  start
}


reload(){

if [ -e $pid_file ] && [ $nginx_process_num -ge 1 ];then
   echo "nginx reload `killall -s HUP $proc`"
else
   echo 'nginx reload failed'

fi
}
status(){
if [ -e $pid_file ] && [ $nginx_process_num -ge 1 ];then

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

}

case $1 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