Add Interactively Unstage Changes as a git til

Author: jbranchaud

README.md

@@ -80,6 +80,7 @@ _326 TILs and counting..._
 - [Grep Over Commit Messages](git/grep-over-commit-messages.md)
 - [Ignore Changes To A Tracked File](git/ignore-changes-to-a-tracked-file.md)
 - [Intent To Add](git/intent-to-add.md)
+- [Interactively Unstage Changes](git/interactively-unstage-changes.md)
 - [Last Commit A File Appeared In](git/last-commit-a-file-appeared-in.md)
 - [List Filenames Without The Diffs](git/list-filenames-without-the-diffs.md)
 - [List Most Git Commands](git/list-most-git-commands.md)

git/interactively-unstage-changes.md

@@ -0,0 +1,21 @@
+# Interactively Unstage Changes
+
+I often use `git add --patch` to interactively stage changes for a commit.
+Git takes me through changes to tracked files piece by piece to check if I
+want to stage them. This same interactive _staging_ of files can be used in
+reverse when removing changes from the index. Just add the `--patch` flag.
+
+You can use it for a single file
+
+```bash
+$ git reset --patch README.md
+```
+
+or you can let it operate on the entire repository
+
+```bash
+$ git reset --patch
+```
+
+This is useful when you've staged part of a file for a commit and then
+realize that some of those changes shouldn't be committed.