Show processes as a tree with parents and children

Lists all processes with user, PID and parent PID (PPID) and indents child processes under their parent. This shows whether a suspicious PHP process belongs to a cron job, to php-fpm or to an SSH session. Append | less -S to page through the long output without line wrapping.

Note: If you prefer pstree: pstree -ap from the psmisc package gives a more compact view.