What data is displayed when executing the 'ps -a' command in Linux?

The ps -a command in Linux displays a list of processes associated with terminals, excluding sessions without a controlling terminal. Specifically, it shows all processes started by all users that are connected to a terminal, except for processes belonging to the terminal session from which the command was invoked.

The output includes PID, terminal, runtime, and command of the process. This is useful for viewing processes of other users running in terminals.

Example output:

  PID TTY          TIME CMD
 1234 pts/0    00:00:00 bash
 2345 pts/1    00:00:01 vim

For more detailed information about processes, ps aux or ps -ef are often used.