Move pages under tldr, lint run.sh, update docs

tldr/git-diff-index

@@ -0,0 +1,25 @@
+---
+syntax: markdown
+tags: [tldr, common]
+source: https://github.com/tldr-pages/tldr.git
+---
+# git diff-index
+
+> Compare the working directory with a commit or tree object.
+> More information: <https://git-scm.com/docs/git-diff-index>.
+
+- Compare the working directory with a specific commit:
+
+`git diff-index {{commit}}`
+
+- Compare a specific file or directory in working directory with a commit:
+
+`git diff-index {{commit}} {{path/to/file_or_directory}}`
+
+- Compare the working directory with the index (staging area) to check for staged changes:
+
+`git diff-index --cached {{commit}}`
+
+- Suppress output and return an exit status to check for differences:
+
+`git diff-index --quiet {{commit}}`