I use the ps command pretty frequently for checking for running processes, and pretty regularly use ps axjf to view currently running processes as a tree. The tree view within ps, though, has always been especially difficult for me to read.

Today, though, I stumbled across pstree, which displays the process tree much more cleanly. It’s installed by default on Ubuntu, so you can run pstree -p to show a tree of all processes, with pids, like this:

pstree output

You can learn more on the pstree man page.