If you name a sql file with .ENV., Roundhouse will start looking for the environment name somewhere on the file. If it doesn't find the proper environment, it will not run the file.
In example, if you name a file LOCAL.permissionfile.env.sql and it is migrating the LOCAL environment, it will run the file. But if it is migrating the TEST environment, it will pass over this file.
Why would I use this?
This is a handy way to insert test data or set custom permissions for an environment.
Does this lock me into RoundhousE?
Only a little, but not really (not like scripts with token replacement in them). If you find yourself in a situation where you needed to manually run scripts, only run the scripts for the particular environment.
That said, I've never heard of/seen a situation where RH failed to work correctly and thus required a manual run. That doesn't mean it would never happen, in the world of software nothing is perfect.