Windows Update from the Command Line

For reference:

run window update from command line? - Windows 7 Help Forums

"yes, you can run it from the command line

%windir%\system32\wuapp.exe startmenu

works but it brings up the gui"

(I find it only works when I remove "startmenu")

This works when adding Windows Update as a Custom item/custom link in Classic Start Menu (Classic Shell) to check for updates, and presumably also in Run.