Add Extend Git With Custom Commands as a git TIL

README.md

@@ -10,7 +10,7 @@ pairing with smart people at Hashrocket.
 
 For a steady stream of TILs, [sign up for my newsletter](https://crafty-builder-6996.ck.page/e169c61186).
 
-_1370 TILs and counting..._
+_1371 TILs and counting..._
 
 ---
 
@@ -271,6 +271,7 @@ _1370 TILs and counting..._
 - [Dry Runs in Git](git/dry-runs-in-git.md)
 - [Exclude A File From A Diff Output](git/exclude-a-file-from-a-diff-output.md)
 - [Excluding Files Locally](git/excluding-files-locally.md)
+- [Extend Git With Custom Commands](git/extend-git-with-custom-commands.md)
 - [Find And Remove Files That Match A Name](git/find-and-remove-files-that-match-a-name.md)
 - [Find The Date That A File Was Added To The Repo](git/find-the-date-that-a-file-was-added-to-the-repo.md)
 - [Find The Initial Commit](git/find-the-initial-commit.md)

git/extend-git-with-custom-commands.md

@@ -0,0 +1,26 @@
+# Extend Git With Custom Commands
+
+I recently learned about the [`git
+absorb`](https://github.com/tummychow/git-absorb) command. It is interesting in
+its own right, but I bring it up because it isn't a command that is built in to
+git. When I was looking at the installation instructions for it, it didn't say
+anything about how to _register_ the command with `git`.
+
+How is git supposed to know about it? How do you extend git with custom
+commands?
+
+What I learned exploring those questions is that `git` will execute any command
+on your _path_ with a `git-<command>` naming convention.
+
+So, if I create a executable binary called `git-taco`, add it to my path, and
+then run `git taco` (notice, no dash when I run it), `git` will run my custom
+binary.
+
+In the same way, if you download `git-absorb` and add it to your path, `git`
+will run it for you when you enter `git absorb ...`.
+
+You can even type something like `where git-` and then hit tab to prompt your
+shell to display a list of a varity of other `git` commands, most of which
+probably ship with `git`.
+
+[source](https://twitter.com/jbrancha/status/1756361704160530555)