Add Dry Runs in Git as a git til.

README.md

@@ -11,6 +11,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 
 - [Checkout Previous Branch](git/checkout-previous-branch.md)
 - [Delete All Untracked Files](git/delete-all-untracked-files.md)
+- [Dry Runs in Git](git/dry-runs-in-git.md)
 - [Intent To Add](git/intent-to-add.md)
 - [Staging Changes Within Vim](git/staging-changes-within-vim.md) 
 - [Stashing Untracked Files](git/stashing-untracked-files.md)

git/dry-runs-in-git.md

@@ -0,0 +1,26 @@
+# Dry Runs in Git
+
+There are a few commands in git that allow you to do a *dry run*. That is,
+git will tell you the effects of executing a command without actually
+executing that command.
+
+For instance, if you are clearing out untracked files, you can double check
+what files are going to be deleted with the *dry run* flag, like so:
+
+```
+$ git clean -fd --dry-run
+Would remove tmp.txt
+Would remove stuff/
+```
+
+Similarly, if you want check which files a commit is going to incorporated,
+you can:
+
+```
+$ git commit --dry-run --short
+M  README.md
+A  new_file.rb
+```
+
+Try running `git commit --dry-run` (that is, without the `--short` flag).
+Look familiar? That is the same output you are getting from `git status`.