在unix启动脚本中检索pid(retrieving pid in unix startup script)

在unix启动脚本中检索pid(retrieving pid in unix startup script)

在我写的一个简单的启动脚本中我有：

PID=`su user_name -c "daemon_name > /dev/null 2>&1 & echo \$!"` echo $PID

该脚本以root身份运行。 回声并没有真正回应:)

如果我在shell中输入完全相同的命令，它可以工作：

# su user_name -c "daemon_name > /dev/null 2>&1 & echo \$!" 11831 #

有任何想法吗？ 谢谢。

编辑：在我尝试以另一个用户身份运行应用程序之前，它工作正常。 我以前使用过这段代码：

PID=`daemon_name > /dev/null 2>&1 & echo $!` echo $PID

它以root身份运行良好

in a simple startup script I wrote I have:

PID=`su user_name -c "daemon_name > /dev/null 2>&1 & echo \$!"` echo $PID

The script is run as root. And the echo doesn't really echo anything :)

If I input the exact same command in the shell, it works:

# su user_name -c "daemon_name > /dev/null 2>&1 & echo \$!" 11831 #

Any ideas? Thanks.

EDIT: It was working fine before I tried to run the application as another user. I was previously using this code:

PID=`daemon_name > /dev/null 2>&1 & echo $!` echo $PID

and it worked fine as root

最满意答案

守护进程被设计为多次fork，因此从$返回的PID很可能！ 不会是你想要以后使用的pid。 您可能需要执行以下操作：

ps -eo pid,command,lstart --sort lstart | grep 'daemon_name' | tail -1

daemons are designed to fork multiple times so likely the PID returned from $! will not be the pid you want to work with later. You will probably have to do something like this:

ps -eo pid,command,lstart --sort lstart | grep 'daemon_name' | tail -1