How do I find out the process id of the backgrounded process?

Question

I've got a command (program) that I'd like to run with nohup and background it. Like

nohup command > logfile.txt &

How do I find out the process ID? I would like to be able to write the process id in a file, read it later and kill the process programatically.

Answer 1

In your script:

nohup command > logfile.txt &
echo $! > /var/run/command.pid

Answer 2

You can use $!. Referenced in the bash documentation.

Answer 3

You could try:

ps aux | grep -v grep | grep program name

That'll check the running processes, grep for the program name, but exclude the grep itself.

Answer 4

You can use ps and grep to find the process in the process list and then awk to parse the output and find the actual PID:

ps -ef | grep -v grep | grep YOUR_PROCESS_NAME | awk '{ print $2 }'