openmd 1.3.1

Fast Markdown previewer for macOS with GitHub-dark theme, sidebar TOC, and multi-file tabs

openmd

A fast, minimal Markdown previewer for macOS with a GitHub-dark theme, collapsible sidebar TOC, live reload, Mermaid diagrams, KaTeX math, and multi-file tab support. Built this for myself because who needs to fire up VS Code or Cursor just to quickly view a pretty printed Markdown file, right?🤣

GitHub: RufusLin/openmd Warning - Lazy Maintainer: Really bad at reading PRs, but will pay attention to issues to fix bugs. Feel free to fork, remember to give credit, please.

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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 aliases (optional)

Add to your ~/.zshrc or ~/.bashrc for quick access:

# Local preview — opens in background
localmd() {
    openmd "$@" >/dev/null 2>&1 &
}

# Remote preview via SSH (requires a 'home' SSH alias in ~/.ssh/config)
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" >/dev/null 2>&1 &
}

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Features

• GitHub-dark theme — comfortable reading in low-light environments. BUT! Change it to whatever you like in .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 — Formulae? inline $…$ and display $$…$$ expressions render out of the box
• Collapsible sidebar TOC — hierarchical, of course; click any heading to jump to it
• 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 — no need to copy and paste file names
• Remote preview — optional remotemd shell alias pulls a file from a remote host via scp and opens it instantly
• Keyboard shortcuts — Esc closes the window; arrow keys navigate the sidebar

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Requirements

• macOS (uses PySide6/Qt WebEngine)
• Python 3.8+
• PySide6
• Markdown
• BeautifulSoup4

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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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Live reload

Openmd watches the opened file for changes using Qt's QFileSystemWatcher. Save the file in any editor (vim, neovim, VS Code, etc.) and the preview — including the sidebar TOC — updates instantly with no manual refresh.

Mermaid & KaTeX

Mermaid and KaTeX are loaded automatically from CDN on every render. No configuration required.

Mermaid example:

```mermaid
graph TD
    A[Start] --> B{Decision}
    B -->|Yes| C[Do it]
    B -->|No| D[Skip]
```

KaTeX example:

Inline: $E = mc^2$

Display:
$$\int_0^\infty e^{-x^2} dx = \frac{\sqrt{\pi}}{2}$$

Note: Mermaid and KaTeX require an internet connection to load from CDN. Offline rendering is not currently supported (maybe never, come to think of it😉).

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Keyboard shortcuts

Key	Action
Esc	Close the preview window
↑ / ↓	Navigate the sidebar TOC
Click heading	Jump to that section

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License

MIT