Linux: processes and resources

Finding and killing processes, CPU and memory, open ports and files, background jobs.

Processes

All processes

ps aux

Find a process by name

pgrep -af <name>

Process tree

ps auxf

Or pstree -p if it is installed.

Top 10 processes by memory

ps aux --sort=-%mem | head -11

Top 10 processes by CPU

ps aux --sort=-%cpu | head -11

Interactive monitor

htop

top is always available; htop is friendlier.

Gracefully stop a process (SIGTERM)

kill <pid>

Force kill (SIGKILL)

kill -9 <pid>

The process can't clean up after itself — use only when SIGTERM doesn't help.

Kill all processes matching a name

pkill -f <name>

Kill whatever listens on a portadvanced

kill $(lsof -t -i :<port>)

Who listens on a port

lsof -i :<port>

All listening TCP ports with processes

sudo ss -tlnp

Files opened by a processadvanced

lsof -p <pid>

Deleted files still held open (disk not freed)advanced

sudo lsof +L1

Memory usage

free -h

Uptime and load average

uptime

CPU, memory and IO every secondadvanced

vmstat 1

Why a process was OOM-killedadvanced

sudo dmesg -T | grep -i -E 'killed process|out of memory'

Run a command immune to logout

nohup <command> > output.log 2>&1 &

List jobs of the current shell

jobs -l

Bring a job to the foreground

fg %1

Ctrl+Z suspends the current command, bg resumes it in the background.

Repeat a command every 2 seconds

watch -n 2 '<command>'