Add Manually Pass Two Git Files To Delta as a Unix TIL

unix/manually-pass-two-git-files-to-delta.md

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+# Manually Pass Two Git Files To Delta
+
+I recently [wired up `delta` as my default pager and differ for
+`git`](git/better-diffs-with-delta.md). However, when I installed `delta`, I
+first wanted to see what its diff output looked like.
+
+How can I pass two versions of the same file from `git` to `delta`?
+
+I can show the current contents of a file with `git show` referencing the
+`HEAD` commit.
+
+```bash
+$ git show HEAD:main.go
+```
+
+Similiarly, I can show the contents of that file _one_ commit ago with `HEAD~`.
+
+```bash
+$ git show HEAD~:main.go
+```
+
+I can then pass each of those commands as virtual files to `delta` using the
+`<()` syntax. The older file goes first and the newer second.
+
+```bash
+$ delta <(git show HEAD~:main.go) <(git show HEAD:main.go)
+```
+
+That works and comes in handy if you need to compare two things that aren't
+necessarily files or aren't necessarily under version control. However, in
+hindsight, I'd say it is easier to add delta as the pager and differ and try it
+out directly.