file called HEAD in your work tree, `git diff HEAD` is ambiguous, and
you have to say either `git diff HEAD --` or `git diff -- HEAD` to
disambiguate.
+
+ * Because `--` disambiguates revisions and paths in some commands, it
+ cannot be used for those commands to separate options and revisions.
+ You can use `--end-of-options` for this (it also works for commands
+ that do not distinguish between revisions in paths, in which case it
+ is simply an alias for `--`).
+
When writing a script that is expected to handle random user-input, it is
a good practice to make it explicit which arguments are which by placing