<p>I have a git repository with multiple branches. </p>

<p>How can I know which branches are already merged into the master branch?</p>

You can use the
```
git merge-base
```
command to find the latest common commit between the two branches. If that commit is the same as your branch head, then the branch has been completely merged.
Note that
```
git branch -d
```
does this sort of thing already because it will refuse to delete a branch that
hasn't
already been completely merged.