ps: Listing Processes

What's running right now?

ps snapshots the process table. There are two flag dialects — BSD (no dash, like ps aux) and SysV (dashes, like ps -ef). On macOS both work; pick the form that's clearer to you and stick with it.

The combos you'll wear out

• ps aux — every process, all users, full command line. The default ps view.
• ps -ef — same idea, SysV style.
• ps -p <pid> — info about one PID.
• ps aux | grep -i firefox | grep -v grep — find by name. The -v grep hides grep itself.
• ps -o pid,ppid,command — pick exactly the columns you want.

The columns you'll care about

• USER — process owner.
• PID — the unique number you'll kill.
• %CPU, %MEM — instantaneous load.
• RSS — resident memory in KB.
• STAT — state (R running, S sleep, Z zombie, T stopped, ...).
• COMMAND — the executable + args. Truncated unless you expand the column.

Pgrep / pkill — find or kill by name

pgrep firefox prints the PIDs. pkill -f 'python myscript' kills every process whose full command matches. Way cleaner than the grep dance.