clean files from .gitignore

Author: hemanth

README.md

@@ -71,6 +71,7 @@
 * [Show inline word diff.](https://github.com/git-tips/tips#show-inline-word-diff)
 * [Don’t consider changes for tracked file.](https://github.com/git-tips/tips#dont-consider-changes-for-tracked-file)
 * [Undo assume-unchanged.](https://github.com/git-tips/tips#undo-assume-unchanged)
+* [Clean the files from `.gitignore`.](https://github.com/git-tips/tips#clean-the-files-from-gitignore)
 
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@@ -497,5 +498,10 @@ git update-index --assume-unchanged <file_name>
 git update-index --no-assume-unchanged <file_name>
 ```
 
+## Clean the files from `.gitignore`.
+```sh
+git clean -X -f
+```
+
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