pslist binary package in Ubuntu Lunar armhf

 pslist is a simple utility to list the process IDs (PIDs) of a process and
 all its children, and its children's children, and so on. If invoked with
 a command name which ends in 'kill', it sends a signal to a selected group
 of processes. If invoked with a command name which ends in 'renice',
 it sets the nice level of the selected group of processes.

Source package