Add Change The Start Point Of A Branch 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/).
 
-_855 TILs and counting..._
+_856 TILs and counting..._
 
 ---
 
@@ -180,6 +180,7 @@ _855 TILs and counting..._
 - [Accessing a Lost Commit](git/accessing-a-lost-commit.md)
 - [Amend Author Of Previous Commit](git/amend-author-of-previous-commit.md)
 - [Caching Credentials](git/caching-credentials.md)
+- [Change The Start Point Of A Branch](git/change-the-start-point-of-a-branch.md)
 - [Checking Commit Ancestry](git/checking-commit-ancestry.md)
 - [Checkout Old Version Of A File](git/checkout-old-version-of-a-file.md)
 - [Checkout Previous Branch](git/checkout-previous-branch.md)

git/change-the-start-point-of-a-branch.md

@@ -0,0 +1,27 @@
+# Change The Start Point Of A Branch
+
+More than a few times I have checked out a new branch against, say, `develop`
+when I instead meant to base it off `qa`. I've tried what felt like the obvious
+solution.
+
+```bash
+❯ git checkout qa
+❯ git checkout -b new-branch
+fatal: A branch named 'new-branch' already exists.
+```
+
+Git won't allow this. The fix I tend to go with is to delete the branch, move
+to my intended starting point, and check it out anew.
+
+Here is another approach. The `git checkout` command offers the `-B` flag which
+will save me a step.
+
+```bash
+❯ git checkout -B new-branch
+Switched to and reset branch 'new-branch'
+```
+
+Use this with caution. Any commits that have been applied to the subject branch
+will be reset (read: wiped out) in the process.
+
+See `man git-checkout` for more details.