How to extract code blocks from Markdown
The extractor keeps each fenced block in source order and shows its first language token, 1-based source lines, and code. Paste Markdown into the page or choose a text file, then inspect the blocks before copying or downloading them. The parser reads code as text and does not execute it.
How to extract fenced code blocks from a Markdown file
- Paste Markdown into Markdown input, or choose Upload and select a
.md,.markdown, or.txtfile. - Read Extracted Code Blocks. Each result shows its order, language, source lines, and code; the status line gives the total found.
- Use Language to choose All languages, one language token, or (none) for blocks without a language token.
- Choose Reset filters to show all extracted blocks, then choose Copy Shown or Download Shown for the visible results.
Filter Markdown code blocks by language
An opening fence can have an info string. The parser takes its first whitespace-delimited token as the language, so ```javascript {#demo} is labeled javascript. A fence with no token appears as (no language) and is listed as (none) in Language.
```js
const total = 3 + 4;
```#1 js Lines 1-3
const total = 3 + 4;The parser keeps the block's order and 1-based start and end lines. Editing the input runs extraction again. Choosing a language filters the results and updates the shown count.
What Copy Shown and Download Shown do
Copy Shown combines the visible blocks with triple-backtick fences and the extracted first language token. It rebuilds the Markdown, so the original fence character, fence length, and extra info-string text are left out. The per-block Copy control copies only the raw code.
Download Shown creates one text download for each visible block. Recognized language tags get mapped extensions such as js, py, or html. Other tags are cleaned for use as an extension; an empty or unusable tag falls back to .txt. Each filename includes the block order and source line range.
How the Markdown fence parser handles edge cases
An opening fence needs at least three backticks or at least three tildes. Its closing fence must use the same character and at least as many characters, with optional spaces or tabs around it. If the closing fence is missing, the block runs to the end of the input and is marked Unclosed fence.
For non-empty input with no recognized fences, the results area says No fenced code blocks found. The parser reads boundaries and code as text; it never evaluates the extracted content. Browser JavaScript handles pasted text and selected file contents, and the page code does not send that content in a request.
Where Markdown code block extraction comes up
- A documentation editor can pull JavaScript and Python examples from a README, then download one language for review.
- A developer comparing generated Markdown can check each snippet's source line range before copying the visible set.
- A technical writer can find unlabeled fenced examples with Language set to (none), then assign language tags where needed.
When another text extractor fits
Use Text Parsing & Data Extraction to choose among text extractors. Extract Markdown Links pulls link labels and destinations from Markdown syntax. Choose Extract Text Between Delimiters for text inside quotes, brackets, parentheses, or custom markers. For a pattern you define, use Custom Regex Extractor.
Frequently asked questions
How do I extract code blocks from a Markdown file?
Choose Upload and select a .md, .markdown, or .txt file. The page parses its text and lists each recognized fenced block with its language, order, and source lines.
Can I extract a fenced block without a language tag?
Yes, a fenced block without a language token appears as (no language). Choose (none) in Language to show those blocks.
How does the Markdown code block Language filter work?
Language matches the first whitespace-delimited token after an opening fence. All languages shows every block. A selected token shows blocks with that label.
Does Copy Shown preserve the original Markdown fence?
Copy Shown uses triple backticks for every visible block and keeps the first language token. It leaves out the original fence character, fence length, and remaining info-string text.