How Do I check the root(/) partition with fsck at boot time?

sudo touch /forcefsck

Then reboot.

or

shutdown -rF now

From man:

The -F flag means 'force fsck'.
This only creates an advisory file /forcefsck which can be tested by the system when it comes up again. The boot rc file can test if this file is present, and decide to run fsck(1) with a special `force' flag so that even properly unmounted file systems get checked. After that, the boot process should remove /forcefsck.

biOos