Add Quicker Commit Fixes With The Fixup Flag as a git til

README.md

@@ -10,7 +10,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 For a steady stream of TILs from a variety of rocketeers, checkout
 [til.hashrocket.com](https://til.hashrocket.com/).
 
-_847 TILs and counting..._
+_848 TILs and counting..._
 
 ---
 
@@ -212,6 +212,7 @@ _847 TILs and counting..._
 - [List Untracked Files](git/list-untracked-files.md)
 - [Move The Latest Commit To A New Branch](git/move-the-latest-commit-to-a-new-branch.md)
 - [Pulling In Changes During An Interactive Rebase](git/pulling-in-changes-during-an-interactive-rebase.md)
+- [Quicker Commit Fixes With The Fixup Flag](git/quicker-commit-fixes-with-the-fixup-flag.md)
 - [Rebase Commits With An Arbitrary Command](git/rebase-commits-with-an-arbitrary-command.md)
 - [Reference A Commit Via Commit Message Pattern Matching](git/reference-a-commit-via-commit-message-pattern-matching.md)
 - [Rename A Remote](git/rename-a-remote.md)

git/quicker-commit-fixes-with-the-fixup-flag.md

@@ -0,0 +1,38 @@
+# Quicker Commit Fixes With The Fixup Flag
+
+Imagine you're working a feature branch and realize that the first commit you
+made had a typo. You could just tack on another commit to fix the typo, but
+that will add noise to your commit history. You can fix it up by making a
+_fixup_ commit.
+
+1. Make your typo fix
+2. Stage the fix
+3. Find the SHA of the commit that you want to fix (e.g. `2ee53ad`)
+4. Create a _fixup_ commit: `git commit --fixup 2ee53ad`
+
+This _fixup_ commit is tied to the original commit it is fixing.
+
+```
+❯ git log --pretty=oneline --abbrev-commit
+b4258b6 (HEAD -> feature-branch) fixup! Add header
+9c0d2b0 Different atomic change
+2ee53ad Add header
+8486b91 (master) Initial commit
+```
+
+To then apply the _fixup_, run `git rebase -i --autosquash master`. This will
+present you with the following _interactive rebase_ screen:
+
+```
+pick 2ee53ad Add header
+fixup b4258b6 fixup! Add header
+pick 9c0d2b0 Different atomic change
+
+# Rebase 8486b91..b4258b6 onto 8486b91 (3 commands)
+```
+
+Because git knows that your _fixup_ commit is tied to `2ee53ad`, it
+automatically moves it into place below that commit with the `fixup` command.
+
+Saving will apply and autosquash the fixup commit leaving you with a clean
+commit history.