Ubuntu is a free computer system, like Windows or macOS, but it’s built by a community. It’s great for programmers because it’s very flexible and has lots of tools already built-in that help you code.

Army Chief of Staff Gen. Randy A. George receives a demo of Next-Generation Command-and-Control system capabilities from a 1st Infantry Division officer. (Sgt. Brahim Douglas/U.S. Army) After spending ...