How do I determine the PID of my python program if there is more then one python program running?

Question

I have two python programs running on my system, say they are called program x and program y.

I want to get the pid of program y, but not x for my bash script. When using pgrep python, I get the pid of both of them and don't know which is which.

Any ideas how I tell the difference between the two in a bash script?

Solution

You can match against the argument list by using the -f switch to pgrep (try man pgrep to read more).

pgrep -f x

should yield only program x and

pgrep -f y

respectively only program y.

As an alternative, if x and y are not unique enough and end in too many rows, you could use ps and grep to have more options

ps ax | grep 'python x' | grep -v grep | awk '{print $1}'

This will

• list all relevant processes
• grep for the ones with python x in it. In here you might need to add a path specifier like python ./path/to/x
• remove the grep command itself from the list of matched processes
• print only the first column, which is the pid.