Add Programmatically Grab SHA For Head Commit as a Git TIL

README.md

@@ -10,7 +10,7 @@ working across different projects via [VisualMode](https://www.visualmode.dev/).
 
 For a steady stream of TILs, [sign up for my newsletter](https://visualmode.kit.com/newsletter).
 
-_1787 TILs and counting..._
+_1788 TILs and counting..._
 
 See some of the other learning resources I work on:
 
@@ -406,6 +406,7 @@ If you've learned something here, support my efforts writing daily TILs by
 - [Move The Latest Commit To A New Branch](git/move-the-latest-commit-to-a-new-branch.md)
 - [Override The Global Git Ignore File](git/override-the-global-git-ignore-file.md)
 - [Pick Specific Changes To Stash](git/pick-specific-changes-to-stash.md)
+- [Programmatically Grab SHA For Head Commit](git/programmatically-grab-sha-for-head-commit.md)
 - [Pulling In Changes During An Interactive Rebase](git/pulling-in-changes-during-an-interactive-rebase.md)
 - [Push To A Branch On Another Remote](git/push-to-a-branch-on-another-remote.md)
 - [Quicker Commit Fixes With The Fixup Flag](git/quicker-commit-fixes-with-the-fixup-flag.md)

git/programmatically-grab-sha-for-head-commit.md

@@ -0,0 +1,33 @@
+# Programmatically Grab SHA For Head Commit
+
+When I use `gh browse path/to/some-file.txt`, it opens the browser to that file
+in GitHub. However, it targets the default branch (`main`) by default which is
+not very useful as a permalink because what that file looks like on `main` is
+liable to change.
+
+There is a `--commit` flag you can use to have it instead open to that file at a
+specific commit SHA.
+
+So what SHA do I pass as an argument to that flag?
+
+Often what I would like to grab is a reference to the current version of the
+file which is whatever it looks like for the `HEAD` commit. But `HEAD` is
+another moving target reference. The `git rev-parse` command can translate
+`HEAD` into a specific SHA though.
+
+```bash
+❯ git rev-parse --short HEAD
+3402428
+
+❯ git rev-parse HEAD
+3402428aadc02cfdc9825c8feb593443e72f50cd
+```
+
+Either of those will work. I can use a bash command substitution then to tie it
+all together into a single command:
+
+```bash
+❯ gh browse path/to/some-file.txt --commit=$(git rev-parse --short HEAD)
+```
+
+See `man git-rev-parse` for more details.