If you modify a program to better fit your site, you probably want to include your modifications when the next release of the program arrives. CVS can help you with this task.
In the terminology used in CVS, the supplier of the program is called a vendor. The unmodified distribution from the vendor is checked in on its own branch, the vendor branch. CVS reserves branch 1.1.1 for this use.
When you modify the source and commit it, your revision will end up on the main trunk. When a new release is made by the vendor, you commit it on the vendor branch and copy the modifications onto the main trunk.
import command to create and update
the vendor branch. When you import a new file,
the vendor branch is made the `head' revision, so
anyone that checks out a copy of the file gets that
revision. When a local modification is committed it is
placed on the main trunk, and made the `head'