This example demonstrates a preprocessing pipeline that transforms Obsidian markdown files into a format suitable for Pandoc conversion to HTML and eventually Word. The script walks a directory tree, merging all `.md` files into a single `merged.md`, while modifying image syntax from `![[...]]` to standard markdown, exposing link URLs, and adding the filename as a top-level heading. It also inserts a non-breaking space between consecutive code blocks to prevent merging. The code relies on Python’s `os.walk` and `re.sub` for file traversal and regex-based text manipulation, with Pandoc invoked externally for the final conversion.