2 examples of on guard duty in sentences

Nearly the entire spring and summer of 1863 was spent in scouring the country in the vicinity of the Tennessee river, sometimes on guard duty, sometimes on the picket line and often in battle.

"That would just suit me, for you see I'm more afraid of going to sleep than anything else while on guard duty," Frank remarked, soberly.

2 examples of  on guard duty  in sentences