Linux Processes Cheat Sheet

ps aux

# Show all processes with user, CPU, memory, and command columns.

ps -ef

# Show all processes with PID, PPID, start time, and command.

ps -u "$USER" -f

# Filter processes by effective user and show full format.

ps -p 1234 -f

# Inspect a specific process by PID.

ps -ef --forest

# Render a process tree using ps output.

pgrep nginx

# Return matching PIDs for a process name pattern.

pgrep -af "python.*worker"

# Match against the full command line and print PID plus command.

pidof sshd

# List the PIDs of a program by executable name.

pstree -ap

# Display process hierarchy with PIDs and arguments.

ps -eo pid,ppid,user,%cpu,%mem,stat,start,time,cmd --sort=-%cpu

# Build a custom process table and sort by CPU usage.

ps -eLf | head

# List lightweight processes or threads.

pgrep -o sshd

# Return the oldest matching PID.

pgrep -n sshd

# Return the newest matching PID.

ps -eo pid,comm,%cpu,%mem --sort=-%cpu | head

# Show the most CPU-intensive processes first.

ps -eo pid,comm,%mem,rss,vsz --sort=-%mem | head

# Show the most memory-intensive processes first.

ps -t pts/0 -f

# Show processes attached to a terminal.

ps --ppid 1 -f

# List child processes of a specific parent.

pgrep -u www-data nginx

# Limit matches to one or more users.

pgrep -s 1234

# Match processes in a session ID.

pgrep -t pts/0

# Match processes running on a specific terminal.

ps -e -o pid,stat,cmd | awk '$2 ~ /^Z/ {print}'

# Find processes in a given state, here zombies.

lsof -iTCP:8080 -sTCP:LISTEN -Pn

# Identify the process bound to a TCP port.

ss -lntp

# List listening TCP sockets with process info.

kill 1234

# Ask a process to terminate gracefully.

kill -9 1234

# Immediately kill a process that is not responding.

kill -HUP 1234

# Commonly used to ask daemons to reload configuration.

kill -STOP 1234

# Suspend execution without terminating the process.

kill -CONT 1234

# Resume a stopped process.

pkill nginx

# Signal all processes whose names match a pattern.

pkill -f "gunicorn: worker"

# Match against full command lines.

pkill -u alice

# Signal all processes owned by a user.

killall node

# Kill all processes that match an executable name.

kill -l

# Print known signal names and numbers.

pgrep -f "celery worker" | xargs kill -TERM

# Signal all matching PIDs found via pgrep.

fuser -k 8080/tcp

# Kill the process that is using a TCP port.

nice -n 10 long-running-job

# Run a command with a niceness offset.

renice 5 -p 1234

# Adjust niceness for an existing process.

chrt -p 1234

# Inspect real-time scheduling policy and priority.

sudo chrt -f -p 50 1234

# Assign a real-time FIFO scheduler to a process.

taskset -c 0,1 myserver

# Pin a command to specific CPU cores.

taskset -cp 0-3 1234

# Inspect or update CPU affinity for an existing process.

ionice -c2 -n7 updatedb

# Run a command with lower I/O priority.

ionice -c3 -p 1234

# Set idle I/O scheduling for a running process.

ulimit -u 4096

# Cap the number of user processes for the current shell.

nohup ./worker.sh > worker.log 2>&1 &

# Keep a process running after the shell exits.

setsid ./server.sh

# Start a process in a new session detached from the terminal.

screen -S myjob

# Use screen for a resumable terminal session.

tmux new -s myjob

# Use tmux for persistent terminal multiplexing.

timeout 30s ./script.sh

# Terminate a command if it runs too long.

time tar -czf backup.tgz /srv/data

# Measure runtime of a command.

watch -n 2 "ps -eo pid,comm,%cpu --sort=-%cpu | head"

# Re-run a command periodically for live monitoring.