Set your email for a repository
If you use git for both work and play, but not necessarily the all on GitHub or the like, it is nice to separate user data like email
Globally:
$ git config --global user.email "your_email@example.com"
Per repository:
$ git config user.email "your_email@example.com"
And when you find out after you have checked out a lot of repositories
$ find . -type d -maxdepth 1 -exec bash -c "cd '{}' ; git config user.email 'your_email@example.com'" \;