Complex sentence: He commanded the 3rd Battalion, 5th Marine Regiment in the Battle of Peleliu where he was wounded by mortar fire and the 1st Battalion, 1st Marine Regiment as well as being Provost Marshal of the 1st Marine Division in the Battle of Okinawa.
Split into simpler sentences: He commanded the 3rd Battalion, 5th Marine Regiment in the Battle of Peleliu where he was wounded by mortar fire. Shofner returned to command the 1st Battalion, 1st Marine Regiment and become Provost Marshal of the 1st Marine Division in the Battle of Okinawa.