如何在Perl中启动外部过程？

Question

I want to start a process, get its PID, and write it to a PID file. I then want to check that file, get the PID, and check if the process is running with kill 0 .

If the process is not running, I want to start it, get its PID, and write it to the PID file. If the process is already running, then I want to ignore it.

How can I start a process so that it keeps running and I can check its status with Perl?

Answer 1

It is traditional on UNIX for a process to manage its own PID file if it is understood that other processes will need its PID as a way to interact with it.

But.. If you use fork/exec to start the process, the parent receives the pid of the child process upon successful fork().

If you give us more detail, we can give more precise help.

--------------------- 2014-11-04 -----------------

Your web services 'should' be creating their own PID files (Many commercially available server solutions do this already). But you don't say how those services are started, nor what kind of processes they are: apache, iis, node, websphere, etc.

In general, this feels like an XY problem. You tell us you want to do X but the bogger picture is that you're doing Y and there's a better way to to Y than just doing X .

So please tell us about the environment and the software.