If you use it to recover from a game-breaking bug (e.g., your fleet gets stuck in a neutron star's beam), you are a hero. If you use it to give yourself 500 Paragons on Cycle 1, you are a villain—but it's a single-player game, so enjoy your villainy.
These are the most commonly used commands to bypass grinding.
These commands are useful for debugging:
Here are some miscellaneous commands: