diff --git a/knowledge base/lint markdown files.md b/knowledge base/lint markdown files.md
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+# Hot to lint markdown files
+
+See [[mdl]].
diff --git a/knowledge base/mdl.md b/knowledge base/mdl.md
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+# Markdown lint tool
+
+Tool to check markdown files and flag style issues.
+
+## TL;DR
+
+```shell
+# Install.
+gem install mdl
+
+# Check files.
+mdl README.md
+mdl path/to/dir/
+```
+
+## Further readings
+
+- [GitHub]
+
+[github]: