A process is simply an instance of a running program. So any program running on your system is a process. All of the following are examples of processes:
- Firefox or any web browser running on your system is a process.
- Your Terminal that you are running right now is a process.
- Any game you may play on your system is a process.
- Copying files is a process.
And just like the case with files, every process is owned by a specific user. The owner of a process is simply the user who started that process.
To list all the processes that are owned by a specific user, you can run the command ps -u followed by the username:
ps -u username
For example, to list all the processes that are owned by elliot, you can run:
root@ubuntu-linux:~# ps -u elliot
PID TTY TIME CMD
1365 ? 00:00:00 systemd
1366 ? 00:00:00 (sd-pam)
1379 ? 00:00:00 gnome-keyring-d
1383 tty2 00:00:00 gdm-x-session
1385 tty2 00:00:18 Xorg
1389 ? 00:00:00 dbus-daemon
1393 tty2 00:00:00 gnome-session...
