How to Use the Command 'rich' (with Examples)

The rich command provides a versatile toolbox for generating fancy outputs in the terminal. Designed to enhance the terminal experience, it extends functionalities such as syntax highlighting, theming, paging, and more, making terminal outputs more visually appealing and informative. More information can be found at its GitHub repository: https://github.com/Textualize/rich-cli .

Use Case 1: Display a File with Syntax Highlighting

Code:

rich path/to/file.py

Motivation: Syntax highlighting is essential for developers and coders as it helps in identifying and differentiating the structure and components of the code easily. By displaying your code files with syntax highlighting, you can quickly spot errors, understand the flow, and aesthetically engage with your work.

Explanation:

• rich: Calls the rich command-line interface to process your request.
• path/to/file.py: This specifies the path to the file you want to be displayed. rich recognizes the file extension and applies appropriate syntax highlighting automatically.

Example Output:
When you run this command on a Python file, for example, you’ll see keywords, strings, comments, and functions color-coded, enhancing readability and making the file look structured and more approachable.

Use Case 2: Add Line Numbers and Indentation Guides

Code:

rich path/to/file.py --line-numbers --guides

Motivation: Adding line numbers and indentation guides can significantly aid in analyzing code. Line numbers help in tracking code segments quickly, especially in debugging and peer review sessions, while indentation guides ensure you can follow code block structuring accurately.

Explanation:

• --line-numbers: This option adds line numbers to every line of code, enabling easier referencing.
• --guides: This option inserts vertical lines that connect indented blocks, making it clearer where swathes of code begin and end.

Example Output:
The command displays each line of your Python file with sequential numbers alongside. Indentation guides appear as vertical lines (often dashed) that visually represent indentations in your code blocks.

Use Case 3: Apply a Theme

Code:

rich path/to/file.py --theme monokai

Motivation: Themes allow for customized aesthetic experiences tailored to the user’s preferences, improving comfort and concentration during long periods of work. Monokai is a popular theme known for its high contrast and balanced color scheme, conducive to reducing eye strain.

Explanation:

• --theme monokai: Applies the “monokai” color theme to the output. Rich supports a variety of themes that can change the color scheme of the syntax highlighting according to the user’s selection.

Example Output:
Running this command on your Python file not only highlights syntax but does so with the vibrant, distinctive colors Monokai is known for, creating a visually striking display on the terminal.

Use Case 4: Display a File in an Interactive Pager

Code:

rich path/to/file.py --pager

Motivation: Long files can be cumbersome to scroll through in a single terminal view. Using an interactive pager facilitates seamless navigation, allowing users to move up and down through the file efficiently, even enabling search functionalities in some cases.

Explanation:

• --pager: Enables the output to be viewed in a pager. This allows for scrolling back and forth through the file instead of displaying it all at once.

Example Output:
The file opens in a pager interface where you can navigate using keyboard arrows. Syntax highlighting remains intact, and the file control is now easier for bigger files.

Use Case 5: Display Contents from a URL

Code:

rich https://raw.githubusercontent.com/Textualize/rich-cli/main/README.md --markdown --pager

Motivation: Directly viewing contents from a URL is highly practical when you need to inspect or present files hosted online, such as documentation or code samples, without downloading them.

Explanation:

• https://...: Direct path to the online file to be displayed.
• --markdown: Indicates that the content is in Markdown format, applying the appropriate formatting styles.
• --pager: As in earlier examples, displays the retrieved file in a paged interface for easier navigation.

Example Output:
Upon execution, the README file from the Rich CLI GitHub repository is fetched, with Markdown syntax revealing bold headers, bullet lists, and other stylized text elements in a page viewer.

Use Case 6: Export a File as HTML

Code:

rich path/to/file.md --export-html path/to/file.html

Motivation: Exporting markdown files to HTML format converts them into a versatile form that can be used for web presentations or further processed with web tools. It is helpful in creating documentation or articles that need to be shared wider than in raw markdown form.

Explanation:

• --export-html: Instructs rich to transform the contents of the markdown file into an HTML document.

Example Output:
The original markdown file is transformed and saved as an HTML file. Opening the newly created HTML file in a web browser will showcase the document with styled elements reflective of its Markdown origins.

Use Case 7: Display Text with Formatting Tags, Custom Alignment, and Line Width

Code:

rich --print "Hello [green on black]Stylized[/green on black] [bold]World[/bold]" --left|center|right --width 10

Motivation: Quickly customizing text for terminal output without writing additional scripts ensures messages are clear and aesthetically appealing. This functionality is suitable for creating banners, alerts, or emphasizing specific outputs in script results.

Explanation:

• --print: Activates the rich text rendering from the command line.
• Hello ...: The text string with Rich markup tags for color and style.
• [green on black]: Text within becomes green on a black background.
• [bold]: Enclosed text is bolded.
• --left|center|right: Aligns text left, center, or right, as specified.
• --width 10: Specifies a line width of 10 characters for the text block.

Example Output:
The terminal outputs the stylized text “Hello Stylized World”. The word “Stylized” appears in green with a black background, while “World” is bolded. Alignment and width specify its position and space usage within the terminal window.

Conclusion:

The rich command opens a variety of possibilities for making terminal interactions more informative and visually appealing. Whether you’re reviewing verbose log files, presenting documentation elegantly, or just improving your code-reading experience with style and syntax highlighting, rich makes the terminal a lively place to be.