How do I find out if my system is using Mir?

Solution 1:

You can also simply check if the system compositor process is running:

 ps afx | grep unity-system-compositor

On my system running Mir it returns something like this:

jorge@jillociraptor:~$ ps afx | grep unity-system-compositor
 4260 pts/0    S+     0:00          |   |               \_ grep --color=auto unity-system-compositor
 1606 ?        S      0:00 /usr/sbin/unity-system-compositor --from-dm-fd 9 --to-dm-fd 13 --vt 7

Machines NOT running Mir will not show unity-system-compositor running.

Reference:

• Running Mir - Olli Reis

Solution 2:

ps -e | grep unity-system-co

Will return one response if Mir is running, nothing if it is not. This is because 'ps -e' actually truncates the process names to 15 characters (known upstream bug/limitation). I found the suggestion from minerz029 always returned nothing even if Mir was running.