How to run nohup and write its pid file in a single bash statement

Question

I want to run my script in background and then write its pid file. I am using nohup to do this.

This is what i came up with,

nohup ./myprogram.sh > /d         


        

Answer 1

Grigor's answer is correct, but not complete. Getting the pid directly from the nohup command is not the same as getting the pid of your own process.

running ps -ef:

root     31885 27974  0 12:36 pts/2    00:00:00 sudo nohup ./myprogram.sh
root     31886 31885 25 12:36 pts/2    00:01:39 /path/to/myprogram.sh

To get the pid of your own process, you can use:

nohup ./myprogram.sh > /dev/null 2>&1 & echo $! > run.pid
# allow for a moment to pass
cat run.pid | pgrep -P $!

Note that if you try to run the second command immediately after nohup, the child process will not exist yet.

Answer 2

This should work:

nohup ./myprogram.sh > /dev/null 2>&1 &
echo $! > run.pid

Answer 3

You already have one ampersand after the redirect which puts your script in background. Therefore you only need to type the desired command after that ampersand, not prefixed by anything else:

nohup ./myprogram.sh > /dev/null 2>&1 & echo $! > run.pid