Sergeant-of-the-Guard
When a battalion is stationed in barracks and not on active service it still has to perform certain public duties as well as protect and safeguard the barracks itself. Back in the day barracks, camp locations and perimeters had to be regularly patrolled and policed allowing only those with the proper authority to both leave or enter the premises at any given times. Overall the Officer-of-the Day would have the ultimate responsibility however he would delegate to the Guard Sergeant the actual duties of inspecting and replacing all of those on patrol and sentry duty at any given time.
Our Sergeant-of-the-Guard goes over the duties and responsibilities of each sentry and members of the Guard as they go on and off duty.