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ComponentsCode Blocks

Code Blocks

Fenced code blocks with syntax highlighting, line highlighting, line numbers, filenames, and word highlighting — powered by Shiki  and rehype-pretty-code .

Code blocks use standard Markdown fenced code block syntax with meta strings for additional features. Copy controls appear when readers hover over or focus a code block.

API

All features are controlled via the meta string after the language identifier:

FeatureSyntaxDescription
Line highlighting\{2,4-6\}Highlight specific lines. Commas separate individual lines, dashes define ranges.
Line numbersshowLineNumbersDisplay line numbers in the gutter.
Filenamefilename="app.py"Display a filename header above the code block.
Word highlighting"print"Highlight all occurrences of a specific word or string.
Disable copycopy=falseHide the hover and focus copy control for a specific block.

Features can be combined in any order on the same code block.

Example

Line highlighting

Highlight specific lines with \{lines\} after the language:

import os
import sys  # highlighted
from pathlib import Path
def main():  # highlighted
    print("hello")  # highlighted
    return 0  # highlighted
```python \{2,4-6\}
import os
import sys  # highlighted
from pathlib import Path
def main():  # highlighted
    print("hello")  # highlighted
    return 0  # highlighted
```

Line numbers

Add showLineNumbers to display line numbers:

import os
import sys
from pathlib import Path
```python showLineNumbers
import os
import sys
from pathlib import Path
```

Filename

Add filename="..." to show a file header:

main.py
def main():
    print("Hello, world!")
```python filename="main.py"
def main():
    print("Hello, world!")
```

Word highlighting

Highlight specific words with quoted strings:

import os
print("hello")
print("world")
```python "print"
import os
print("hello")
print("world")
```

Combined features

All meta features work together:

app.py
import os
import sys  # highlighted line, with line numbers and filename
from pathlib import Path
```python \{2\} showLineNumbers filename="app.py"
import os
import sys  # highlighted line, with line numbers and filename
from pathlib import Path
```
CalloutCodeGroup