Add What Changed? as a git til

README.md

@@ -7,7 +7,7 @@ variety of languages and technologies. These are things that don't really
 warrant a full blog post. These are mostly things I learn by pairing with
 smart people at [Hashrocket](http://hashrocket.com/).
 
-_502 TILs and counting..._
+_503 TILs and counting..._
 
 ---
 
@@ -158,6 +158,7 @@ _502 TILs and counting..._
 - [Untrack A Directory Of Files Without Deleting](git/untrack-a-directory-of-files-without-deleting.md)
 - [Untrack A File Without Deleting It](git/untrack-a-file-without-deleting-it.md)
 - [Verbose Commit Message](git/verbose-commit-message.md)
+- [What Changed?](git/what-changed.md)
 - [What Is The Current Branch?](git/what-is-the-current-branch.md)
 - [Whitespace Warnings](git/whitespace-warnings.md)
 

git/what-changed.md

@@ -0,0 +1,37 @@
+# What Changed?
+
+If you want to know what has changed at each commit in your Git history,
+then just ask `git whatchanged`.
+
+```bash
+$ git whatchanged
+
+commit ddc929c03f5d629af6e725b690f1a4d2804bc2e5
+Author: jbranchaud <jbranchaud@gmail.com>
+Date:   Sun Feb 12 14:04:12 2017 -0600
+
+    Add the source to the latest til
+
+:100644 100644 f6e7638... 2b192e1... M  elixir/compute-md5-digest-of-a-string.md
+
+commit 65ecb9f01876bb1a7c2530c0df888f45f5a11cbb
+Author: jbranchaud <jbranchaud@gmail.com>
+Date:   Sat Feb 11 18:34:25 2017 -0600
+
+    Add Compute md5 Digest Of A String as an Elixir til
+
+:100644 100644 5af3ca2... 7e4794f... M  README.md
+:000000 100644 0000000... f6e7638... A  elixir/compute-md5-digest-of-a-string.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.