dev is the general-purpose dev tool for working on cockroachdb/cockroach; it's powered by Bazel underneath the hood. With it you can:

• build various binaries (cockroach, roachprod, optgen, ...)
• run arbitrary tests (unit tests, logic tests, ...) under various configurations (stress, race, ...)
• generate code (bazel files, docs, protos, ...)

You can use the top-level ./dev script instead of building a dev binary ahead of time. This script just does it for you whatever version is checked out and immediately runs it with the supplied arguments. Run dev --help to see what it can do!