Run commands only if they haven’t been run before in this world.
If you are looking for a way to run commands once when you start a new fortress, you probably want on-new-fortress.
This tool is better for commands that you want to run once per world.
You can specify multiple commands to run, separated with ;, similar to
multicmd. However, if the command has been run (successfully) before with
once-per-save in the context of the current savegame, the commands will not
once-per-save [--rerun] <command>[; <command> ...]
Run the specified commands if they haven’t been run before. If
--rerunis specified, run the commands regardless of whether they have been run before.
Forget which commands have been run before.