HOOAH (USArmy) or OORAH (USMC) is a military expression of enthusiastic agreement.  The acronym associated with it, HUA,
stands for Heard, Understood, Acknowledged.

"GARY OWEN"  (USARMY) is actually Garryowen…all one word… and it is the Regimental marching song of the famous 7th Cavalry.   Can be used the same way HOOAH or OORAH is used.

Semper Fi – shortened version of "Semper Fidelis", the motto of the USMC, Latin for "always faithful".

"HONOR, COURAGE, COMMITMENT" USN No official motto

US Navy Core Values
(No official motto)