linux判断进程或者cron是否存在shell

#!/bin/bash

var=$(ps -ef | grep process_name | grep -v grep | wc -l)

if [ $? = 0 ] ;

then

echo " this program is not exist!"

else

echo " this program is exist!"

fi

(process_name为进程名字)把以上存为一个.sh后缀的文件，执行方法： ./test.sh