Add Intent To Add as a git til.

git/intent-to-add.md

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+# Intent To Add
+
+Git commands like `git diff` and `git add --patch` are awesome, but their
+little caveat is that they only work on files that are currently tracked in
+the repository. That means that after working on that new feature for 30
+minutes, a `git diff` is only going to show you the changes to existing
+files and when you go to start making commits with `git add --patch` you
+will again be provided with only part of the picture.
+
+The `git add` command has a flag, `-N`, that is described in the git man
+pages:
+
+> Record only the fact that the path will be added later. An entry for the
+> path is placed in the index with no content. This is useful for, among other
+> things, showing the unstaged content of such files
+> with git diff and committing them with git commit -a.
+
+By adding untracked files with the `-N` flag, you are stating your *intent
+to add* these files as tracked files. Once git knows that these files are
+meant to be tracked, it will know to include them when doing things like
+computing the diff, performing an interactive add, etc.