Questions about example sentences with, and the definition and usage of "Oopa"

A: I am guessing it was a military movie? "Ooh-ra" pronounced like the "oo" in "too" then with "ra" like "rally". Is basically like the war cry of the US marine corps. It can be used as a celebratory sound, marines use it to identify other marines, or to kinda rally your troops.

If it was "Opa!" like the "o" from "open" and "pa" as in "pasta". That is a greek word used in celebration.

Seems odd to be the second in a military movie. So it is probably the marine cry. So in that context, i agree probably means we did it! :)