So what you really want is a tool that can easily identify your changes compared to other changes in the merge conflict, rather the author of each line (what would it mean), right?
If I understand you correctly, I have relatively good news: it can be done with git + kdiff3. For merging, you can simply use git mergetool (which you can configure to use kdiff3). But it is not supported initially if you get a merge conflict when performing an interactive reboot, so this requires several manual scripts.
Instead of compiling my own example of a simple conflict merge, I will use http://www.gitguys.com/topics/merging-with-a-conflict-conflicts-and-resolutions/ as the basis. Follow this page until the git merge test . After merging the command, I deviate a little from this example by running different commands (but basically do the same job). First I will do all the basic steps.
So, we have a merge conflict, and git inserted content from both providing sources in a file in this format <<<<<<<...>>>>>>> , which I really don't like at all, and never consider even looks at him. Instead, I use my favorite merge tool, kdiff3.
First we need to find which versions will be involved.
$ git ls-files -u 100644 b0ed415d15862ac5582b51e4de65528e86934cd2 1 README 100644 56300e3ac4e4521c3500618a301bb2ab2d6a52f5 2 README 100644 9585db7d9c2d9ca05075f67a878f2554886d7b1a 3 README $
I deceived this information, which we can do in three ways:
$ git cat-file blob b0ed415d15862ac5582b51e4de65528e86934cd2 > v1 $ git cat-file blob 56300e3ac4e4521c3500618a301bb2ab2d6a52f5 > v2 $ git cat-file blob 9585db7d9c2d9ca05075f67a878f2554886d7b1a > v3 $ kdiff3 -o merge_result v1 v2 v3 & [2] 18394 $
Which gives the following view, where you can choose from which ancestor you want to merge.

Afterwords (if you are satisfied with the result of the merger) you need
$ rm v1 v2 v3 $ mv merge_result README $ git add README
All of the above steps are manually performed automatically with git mergetool . So why show it all? Good, because if you get the corresponding conflict during git rebase -i , then it should be done this way (before running git rebase --continue ).
In this small example, there is only one conflict, so it does not show a more typical case when many lines are automatically resolved, which allows you to simply manually resolve which were not performed automatically. A more real life example might look like this:

Note that as a result of the merge, you now clearly see the beginning of C lines that were automatically resolved. I think this is what you asked for when you asked for an author for each line, right? This information is completely absent in the text <<<<<<<...>>>>>>> (and it is difficult / impossible to determine that you must update the printed line in the hello function).
I can not recommend kdiff3 highly enough. Using a graphical merge tool like this, compared to some lines from both sources, mixed inside a line in a file, like using an excavator compared to spade .