Hi,
Yes, no problem.
A pull is just a fetch and a merge. And a merge is a commit with more
than one parent. So you can use the command "git reset --hard HEAD^" to
undo a merge, just as you can undo any other commit.
NOTE: if you pushed that commit (merge or not), do _not_ use reset. This
effectively rewrites history, and _will_ upset people pulling from you.
If you really have to undo a commit you already published, use "git revert
<commit>".
Hth,
Dscho
-