In a parallel development environment, the opposite of branching is merging. In the simplest scenario, merging incorporates changes on a subbranch into the main branch. However, you can merge work from any branch to any other branch. Automated merge facilities are included for handling almost any scenario.
One of the most powerful Rational® ClearCase® features is source control of directories.
On a Windows® system, each version of a directory element catalogs a set of file elements and directory elements.
On the UNIX® system or Linux®, each version of a directory element catalogs a set of file elements, directory elements, and VOB symbolic links.
Merging work from many branches to a single branch is also supported; this is typically a project manager's or integrator's task.
You can merge versions outside of Rational ClearCase, but a merge arrow is not created for you. You must create it manually.