Managing Linux processes (ps, top, htop, kill)

Listing Processes with ps

# show your processes
ps

# show all processes with details
ps aux

# search for a specific process
ps aux | grep ssh

The columns show PID (process ID), USER, CPU and memory usage, and the command running.

Monitoring Processes with top

top

top updates in real time, showing CPU, memory usage, and active processes. Useful keys:

• P – sort by CPU
• M – sort by memory
• K – kill a process (enter PID)
• Q – quit

htop (Improved top)

Install it first:

# Ubuntu/Debian
sudo apt install -y htop

# CentOS/AlmaLinux
sudo dnf install -y htop

Launch with:

htop

htop shows a color-coded, interactive view. Use arrow keys to navigate, F9 to kill, F10 to quit.

Killing Processes

# kill by PID
kill 1234

# force kill
kill -9 1234

# kill by process name
pkill firefox

# kill all matching processes
killall apache2

Use kill -9 only if a process ignores normal signals.

Checking Resource Usage

# show CPU usage
uptime

# show memory usage
free -h

# show disk usage
df -h

Combine these with process commands for better system monitoring.