Fixes#4808 by extracting the full username by:
- Get PID using pgrep
- Get UID from PID using /proc/${PID}/loginuid
- Get user name from UID using id
Also replaces "complex" pipe from ps to sed with a (hopefully) "simpler" (as in requiring less knowledge about the arguments of ps and regexps) invocation of cat and id.
9bd578d4ea