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# List all running processes (BSD style)
ps aux

# List processes in forest/tree view
ps auxf

# List processes for current user
ps -u $USER

# Find a specific process
ps aux | grep nginx
pgrep nginx           # Returns just the PID(s)
pgrep -l nginx        # Returns PID and name

# Show process tree
pstree
pstree -p             # Include PIDs
pstree -u             # Include usernames

# ---- top ----
top
# Keyboard shortcuts inside top:
# q       quit
# M       sort by memory
# P       sort by CPU (default)
# k       kill process (enter PID)
# r       renice process
# 1       toggle per-CPU display
# H       show threads
# u       filter by username

# ---- htop (install: sudo apt install htop) ----
htop
# F5 = tree view | F6 = sort | F9 = kill | F10 = quit

# ---- Process states ----
# R  Running
# S  Sleeping (interruptible)
# D  Sleeping (uninterruptible, usually I/O wait)
# Z  Zombie (finished but parent hasn't collected exit status)
# T  Stopped / traced

# Watch a command's resource use in real time
watch -n 1 'ps aux --sort=-%cpu | head -15'