He's asking for a "pre-commit" hook. Piping little wrappers into your local environment doesn't scale, doesn't automate, doesn't prevent someone else using "TortoiseSVN" from overriding the desired filter, etc., etc.
There are many Google accessible answers, but perhaps our hero can start with a classic example at https://stackoverflow.com/questions/16751653/unable-to-generate-output-from-svn-pre-commit-hook .
