Add Programmatically Grab SHA For Head Commit as a Git TIL

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

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+# 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.