While working on one of our projects which uses SVN for version control, I had to merge in some changes from trunk to the branch. I did this as explained below:
First checkout the branch where you want to merge revisions from trunk
svn co http://svn_repo_url/project/branches/branch my_branch
svn log -v --limit 100 # list most recent 100 svn commits with messages
Say you want to merge trunk revisions 101, 102, 103 and 104 into branch
svn merge -c 101 -c 102 -c 103 -c 104 http://svn_repo_url/project/trunk
You should see something like this for all the revisions which get merged into the branch.
--- Merging r101 into '.':
--- Recording mergeinfo for merge of r101 into '.':
Resolve conflicts if any and commit.