A field guide to the vi family: from 1977 original to LLM-era forks

A catalog of vi lineage editors, starting with Bill Joy’s 1977 original and tracing the branches that emerged after AT&T’s commercial UNIX licensing pushed developers to build free clones in the 1980s. STevie spawned Vim, which became the dominant clone with multi-buffer support, scripting, and gigabyte-file handling. Elvis influenced nvi, which became the BSD reference implementation and later sprouted OpenVi and the UTF-8-capable nvi2. Smaller niches are covered too: BusyBox vi for embedded systems, IllumOS vi preserving the AT&T SVR4 code, and tiny clones like xvi.

The modal-editing concept also leaked outside the family proper. Viper and Evil bolt vi keybindings onto Emacs, while Kakoune, vis, and Helix are newer modal editors that borrow the philosophy but break compatibility on keystrokes. The author notes that vi bindings are now standard options in VS Code, IntelliJ, and Xcode, which is part of why a 50-year-old editor remains relevant.

The most current development is a schism over AI-generated code. Both Vim and Neovim have begun accepting LLM-written contributions, prompting 2026 forks: EVi and Vim Classic (based on Vim 8.3) explicitly position themselves as human-maintained continuations from the pre-LLM codebase. It’s an early concrete example of open-source projects forking on AI-contribution policy rather than technical direction.