Comment 5 for bug 353278

> polkit-auth --obtain org.freedesktop.packagekit.system-update

for me it just hangs there without showing any output, after several minutes it will output

Attempting to obtain authorization for org.freedesktop.packagekit.system-update.
Authentication as an administrative user is required.

and continues idling without exiting so I closed with ctrl+c

something seems bugged, I can try the same command with "org.asdasdasd.asdasd" and It will not error out, it will idle several minutes before showing any error messages and exit.