Merge contributers by aliases to show commit count in shortlog.

When contributors add to a project from different machines or operating systems, it may happen that they use different email addresses or names for this, which will fragment contributor lists and statistics.

Running git shortlog -sn to get a list of contributors and the number of commits by them could result in the following output:

Patrick Rothfuss 871
Elizabeth Moon 762
E. Moon 184
Rothfuss, Patrick 90

This fragmentation/disassociation may be adjusted by providing a plain text file .mailmap, containing email mappings.

All names and email addresses listed in one line will be associated to the first named entity respectively.

For the example above, a mapping could look like this:

Patrick Rothfuss <fussy@kingkiller.com> Rothfuss, Patrick <fussy@kingkiller.com>
Elizabeth Moon <emoon@marines.mil> E. Moon <emoon@scifi.org>

Once this file exists in the project’s root, running git shortlog -sn again will result in a condensed list:

Patrick Rothfuss 961
Elizabeth Moon 946