Master Linux Process Management: Using ps, kill, and killall

Understanding Linux Processes

In Linux every program and daemon runs as a process. Each process consumes memory and CPU cycles, so the more processes you run, the higher the resource usage. On older or low‑power machines (e.g., a 7‑year‑old laptop or a Raspberry Pi) monitoring background processes can help you make the most of limited resources.

Listing Processes with ps

The ps command displays currently running processes. Common options are: -e – show every process -f – full‑format listing with additional columns

Examples:

$ ps -e -f

PID TTY          TIME CMD
88000 pts/0      00:00:00 bash
88052 pts/0      00:00:00 ps
88053 pts/0      00:00:00 head

$ ps -e | head

PID TTY          TIME CMD
    1 ?        00:00:50 systemd
    2 ?        00:00:00 kthreadd
    3 ?        00:00:00 rcu_gp
    4 ?        00:00:00 rcu_par_gp

$ ps -ef | head

UID          PID    PPID  C STIME TTY          TIME CMD
root        10013   51   0 00:00:50 /usr/lib/systemd/systemd --switched-root --system --deserialize 36
root        20013   51   0 00:00:00 [kthreadd]
root        32013   51   0 00:00:00 [rcu_gp]
root        42013   51   0 00:00:00 [rcu_par_gp]

Interpreting ps Output

Key columns include: UID – user that owns the process PID – numeric process identifier PPID – parent process identifier

Process numbering starts at 1; the first user‑space process is systemd (PID 1), which spawns kthreadd, and that in turn creates other kernel threads such as rcu_gp and rcu_par_gp.

Terminating Processes with kill

When a program like Chromium leaves many background processes after you close the UI, you can terminate them with kill. First obtain the PIDs, then feed them to kill:

$ ps -ef | fgrep /usr/lib64/chromium-browser/chromium-browser | awk '{print $2}' > /tmp/pids
$ kill $(cat /tmp/pids)

The first command extracts all Chromium process IDs; the second kills each of them in one shot.

Using killall for Bulk Termination

The killall command can terminate every process whose executable name matches a pattern, providing a quicker way to stop many similar processes: $ killall chromium-browser Because killall matches by name, it is advisable to first verify the target processes with ps -ef. killall also supports useful options: -i or --interactive – prompt before killing each process -o or --older-than – select processes older than a given time -y or --young-than – select processes newer than a given time

Alternative Management via Chromium Settings

Instead of killing processes manually, Chromium provides a built‑in setting to control background activity. Disabling “Continue running background apps when Chromium is closed” stops the extra processes from persisting after you exit the browser.

Regularly checking which processes are running and intervening when necessary remains a good practice for system stability.