How many people were involved in a project? Based on Revision Control System

Question

How do you know how many developers were involved in a project using a Revision Control System? A friend of mine found this way to look up the answer in git log:

git log | grep Author: | sort -u | cut –delimiter=” ” -f2 | sort -u | wc -l

Is there a straightforward way in git? How about other Revision Control System like Subversion, Bazaar or Mercurial?

Answer 1

git

The shortlog command is very useful. This summarizes the typical git-log output.

$ git shortlog -sn
   119  tsaleh
   113  Joe Ferris
    70  Ryan McGeary
    45  Tammer Saleh
    45  Dan Croak
    19  Matt Jankowski
    ...

Pass to wc to see the number of unique usernames:

$ git shortlog -sn | wc -l
      40

Answer 2

For mercurial, there's an extension to do exactly that: hg churn.

hg churn sorts by line-changed, if you want changeset count, use hg churn -c.