进程锁

防止进程被重复运行

[root@aliyun ~]# cat lock.sh 
#!/bin/bash
lock_file=/tmp/echo1.lock

#判断进程是否正在运行
if [ -f $lock_file ];then
    pid=`cat $lock_file`
    ps $pid &>/dev/null
    [ $? -eq 0 ] && echo "Script1 is running..." && exit 1
    #if [ $? -eq 0 ];then
    #   echo "Script1 is running..."
    #   exit 1
    #fi
fi

#创建锁
echo $$ > $lock_file

echo "lock1 begin..."
sleep 500
echo "lock1 end"

#释放锁
rm -rf $lock_file