A text editor that launches before your finger leaves the key.

mu is a macOS-native GUI text editor built for one thing: getting out of your way. No project files, no plugins, no settings to tweak. Just type mu notes.txt and start writing.

Terminal editors are fast but modal. GUI editors are friendly but slow. mu is both — a native AppKit window that pops up instantly from your terminal, with every macOS keybinding you already know.

• Instant startup — ~60KB native binary, no framework overhead, no Electron, no JVM
• Zero learning curve — if you can use TextEdit, you can use mu
• Terminal-first — launched from the command line, stays out of your Dock
• One job, done well — edit text, save with ⌘S, done
• Line-aware — line numbers are always visible, and ⌘L jumps straight to a line

curl -fsSL https://github.com/T45K/mu/releases/download/v0.2.0/mu -o ~/.local/bin/mu
chmod +x ~/.local/bin/mu

make
ln -sf "$(pwd)/mu" ~/.local/bin/mu    # or wherever your PATH points

mu filename.txt        # open existing file or create new
mu                     # open a scratch buffer (/tmp/mu.txt, cleared on each launch)

That's it.

mu follows standard macOS conventions. Everything works the way you expect:

Find is case-insensitive and wraps around when it reaches the beginning or end of the document. Line numbers are shown in the left gutter, including an empty final line after a trailing newline. Press ⌘L, type a line number in the lightweight inline field, and press Return to move the cursor to the start of that line.

• macOS 13+
• Swift toolchain (Xcode Command Line Tools)

MIT