Inspecting Processes

Command	Purpose
`ps aux`	Snapshot of all processes (BSD style)
`ps -ef`	Snapshot (System V style)
`top` / `htop`	Live, interactive view
`pgrep -a nginx`	Find PIDs by name
`pstree`	Process hierarchy
`uptime`	Load averages

Load average shows demand over 1, 5, 15 minutes. A value roughly equal to your CPU count means fully loaded.

$ ps -ef | head -2
UID   PID  PPID  C STIME TTY   TIME     CMD
root    1     0  0 09:00 ?     00:00:02 /sbin/init

Exam tip: PID 1 is init/systemd. Every process has a parent (PPID); orphans are re-parented to PID 1.