openmd 1.4.18

Fast Markdown previewer with GitHub-dark theme, sidebar TOC, multi-file tabs, and .openmd.css theming

openmd

Markdown viewer for humans — not AI models.

I got tired of reading raw Markdown with less or opening VS Code/Cursor just to see it nicely rendered. So I built openmd.

Run openmd *.md (or any Markdown files) from the shell and a window pops up instantly — the shell prompt returns immediately, no blocking, no & needed.

GitHub: RufusLin/openmd

Warning - Lazy Maintainer: Yeah, not a fan of reading PRs, but will pay attention to issues to fix bugs. Feel free to fork, but remember to give credit, please.🙏🏻

X: @rufuslinjapan

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What it looks like

(Click any image to enlarge)

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Usage

# Open a single file
openmd README.md

# Open multiple files (each in its own tab)
openmd doc1.md doc2.md doc3.md

# No arguments — interactive picker (choose from .md files in current directory)
openmd

# Glob expansion
openmd docs/*.md

Shell function (optional, for quick access)

Add to your ~/.zshrc or ~/.bashrc:

openmd() { "$HOME/lab/openmd/openmd.py" "$@" 2>&1 }

Or if installed via pip, the openmd command is already in your PATH.

Remote preview via SSH (optional)

remotemd() {
    local remote_path="$1"
    local filename=$(basename "$remote_path")
    local tmp_file="/tmp/remote_preview_${filename}.md"
    scp "home:$remote_path" "$tmp_file" && openmd "$tmp_file"
}

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Features

• Instant launch — the shell prompt returns immediately; openmd runs as a fully detached GUI app (no & needed, no blocking)
• GitHub-dark theme by default — comfortable reading in low-light environments
• 16 built-in themes — dark and light, switch instantly via the swatch bar at the bottom of the sidebar; fully customizable via .openmd.css
• Live reload — the preview updates instantly when the file is saved; no manual refresh needed
• Mermaid diagrams — fenced ```mermaid blocks render automatically via CDN
• KaTeX math — inline $…$ and display $$…$$ expressions render out of the box
• Collapsible sidebar TOC — hierarchical (H1 → H2 → H3); click or press Return to jump to any heading
• Multi-file tabs — pass multiple .md files (even *.md globs) and each opens in its own tab, max 6
• Interactive file picker — run with no arguments and choose from .md files in the current directory via a curses-based picker
• Remote image caching — remote images in your Markdown are downloaded to a local temp cache so they render correctly in the Qt WebEngine view
• External link handling — clicking any http/https link opens it in your default browser; the preview window never navigates away
• Update notifications — on startup, openmd quietly checks PyPI (at most once every 6 hours) and shows a non-intrusive popup if a newer version is available
• Version in title bar — the window title shows the running version for quick reference
• Keyboard shortcuts — Esc closes the window; arrow keys and Return navigate the sidebar

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Theming with .openmd.css

openmd ships with 16 built-in themes (8 dark, 8 light) selectable from the swatch bar. To customize further, create a .openmd.css file — it is appended after the built-in CSS so any rule you write overrides the default via normal CSS cascade.

Lookup order (first match wins):

Priority	Location
1	Current working directory (./)
2	openmd install directory
3	Home directory (~/)

To switch themes programmatically, add body.theme-yourname { ... } blocks to your .openmd.css. The swatch bar automatically discovers and displays any themes defined there.

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Requirements

• macOS or Linux (POSIX)
• Python 3.8+
• PySide6 + PySide6-WebEngine
• Markdown
• BeautifulSoup4

Note: Mermaid and KaTeX require an internet connection to load from CDN.

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Installation

pip (recommended)

pip install openmd

After installing, the openmd command is available in your shell.

From source

git clone https://github.com/RufusLin/openmd.git
cd openmd
pip install -e .

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Keyboard shortcuts

Key	Action
Esc	Close the preview window
↑ / ↓	Navigate the sidebar TOC
Return	Jump to selected heading

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License

MIT