From How do I Shutdown - Restart - Logoff Windows via bat file

Here’s how to do the shutdown functions via a batch file:

REM restarts
shutdown -r
REM shuts down
shutdown -s
REM logoff
shutdown -l
REM where xx is number of seconds to wait till shutdown/restart/logoff
shutdown -t xx
REM gives you a dialog box to fill in what function you want to use
shutdown -i
REM aborts the previous shutdown command....very handy!
shutdown -a
REM hibernate. Easy mistake - it's not for help
shutdown -h

Additional options:

REM force the selected action