If you want to know what has changed at each commit in your Git history, then just ask git whatchanged.

$ git whatchanged

commit e961c93a0ef1f59d56cdf740fd400470bd47d504
Author: Naren <naren@narendasan.com>
Date:   Wed Apr 12 15:30:17 2017 -0700

    a attribution

:100644 100644 bb1ad6c... 0bd0aa8... M  index.md

commit ae3683134c485a9ad42268179047a1bf71b50b53
Author: Naren <naren@narendasan.com>
Date:   Wed Apr 12 15:28:26 2017 -0700

    a Jekyll site

:000000 100644 0000000... c442299... A  .gitignore
:000000 100644 0000000... aa65c1c... A  404.md
:000000 100644 0000000... 1090241... A  CONTRIBUTING.md
...

This is an old command that is mostly equivalent to git-log. In fact, the man page for git-whatchanged says:

New users are encouraged to use git-log(1) instead.

The difference is that git-whatchanged shows you the changed files in their raw format which can be useful if you know what you are looking for.

See man git-whatchanged for more details.