Let's say you just fixed a bug in kde-apps and you commited it to the master and git reported it as commit id 0f601b3d28. You want now to get it backported to the latest released version.
When you issue:
git branch -a
remotes/origin/4.6 remotes/origin/HEAD -> origin/master remotes/origin/KDE/4.0 remotes/origin/KDE/4.1 remotes/origin/KDE/4.2 remotes/origin/KDE/4.3 remotes/origin/KDE/4.4 remotes/origin/KDE/4.5 remotes/origin/KDE/4.6 remotes/origin/kdepim/enterprise-4.0.83 remotes/origin/kdepim/enterprise-4.1 remotes/origin/master
The red-colored lines are showing you the branches that are living into the main repository (you must have enabled git colors before this).
You need to backport to the last released version, which lives in the remotes/origin/KDE/4.6:
git checkout -b KDE/4.6 origin/KDE/4.6
This will get get you on the backport branch. Verify the diff between this old branch and the origin branch where you commited your fix :
git diff origin <fileYouModified>
To apply your fix, do this:
git cherry-pick 0f601b3d28
You just applied your fix (well, if you get merging errors, just fix them as usual). See it by yourself:
Now push your changes:
Don't forget to get back on the main branch:
git checkout master