Git commit messages:
http://tbaggery.com/2008/04/19/a-note-about-git-commit-messages.html
A way to write multilines commit message in one line in bash:
http://stackoverflow.com/questions/5064563/add-line-break-to-git-commit-m-from-command-line
This is good:
git commit -m $'summary\n\ndescription'
because it stays tidy and clean in history
Histogram and commands how to generate them:
http://stackoverflow.com/questions/2290016/git-commit-messages-50-72-formatting