Process Management: ps, top, htop, and Signals

Finding and managing processes — identifying CPU/memory hogs, killing stuck processes, and understanding process trees — requires different tools for different situations.

Use ps for scripting, top/htop for interactive monitoring, and kill with specific signals.

# Find processes by name
ps aux | grep nginx
pgrep -la nginx

# Process tree
pstree -p
ps axjf

# Top CPU consumers
ps aux --sort=-%cpu | head -15

# Top memory consumers
ps aux --sort=-%mem | head -15

# Kill process gracefully (SIGTERM)
kill 1234

# Kill forcefully (SIGKILL) — last resort
kill -9 1234

# Kill all processes matching a name
pkill -f 'python manage.py'

# Send signal to process group
kill -TERM -$(pgrep -f myapp)

# Wait for a process to finish
wait 1234

SIGTERM (15) asks the process to clean up and exit gracefully. SIGKILL (9) cannot be caught or ignored — it terminates immediately but may leave temp files or locks behind. Always try SIGTERM first.