SubEthaEdit

The editor provides a macOS‑native environment for writing plain, code, and notes, supporting collaborative sessions where multiple participants can edit the same document in real time. It includes fine‑grained undo that tracks individual edits, block editing for simultaneous line changes, and a live web preview that refreshes HTML, CSS, and JavaScript automatically on save. Users can open split views or multiple windows of a single file, employ regex‑based search and replace with multiple result panes, and navigate with line numbers, folding, and brace matching.

A command‑line front‑end named “see” lets the application be used as a default Unix editor, while full AppleScript support enables automation and custom workflows. The interface adapts to macOS Mojave dark mode and offers extensive system integration.

The software ships with an extensible mode infrastructure covering dozens of programming and markup languages, each providing syntax highlighting, customizable style hierarchies, and autocomplete. New language modes can be added easily, encouraging community contributions.