Clearcase: how to rollback all changes on specific branch?

I made a bug fix on bug fix branch, but now I need to开发者_开发知识库 rollback all change on this branch. How to do that? I don't want to revert each file one by one, :(.

I didn't test it recently, but check out the perl script available with a ClearCase installation called cset.pl (also available here):

ccperl cset.pl -undo myActivity

It should undo an activity by performing a negative merge (or substractive merge).
(That is, supposing you are using UCM since you are mentioning "changeset", which means "UCM activity")