Butterfish Shell

What is Butterfish Shell?

Butterfish Shell is a command-line tool that integrates OpenAI-powered AI prompting directly into bash and zsh. It provides context-aware help, suggests commands, and supports high-context AI conversations without ever leaving the terminal.

Peter Bakkum created the project and released it as open source under the MIT License. The goal is to make working with large language models (LLMs) faster and more effective, keeping the experience natural and ergonomic inside the shell — no extra windows or mouse clicks. Butterfish works alongside your existing shell setup by intercepting input and output and communicating with the OpenAI ChatGPT API.

Key features

• Smart command assistance: AI prompting inside bash and zsh, with command suggestions and help.
• Contextual conversations: Chat with the AI using your shell history, so responses are relevant to what you’re working on.
• Autocomplete and autosuggestions: Speed up the command line with AI-powered suggestions based on your recent history and ChatGPT prompts.
• Goal Mode: State an objective and Butterfish autonomously runs commands to achieve it.
• Direct queries: Ask questions, find out why a command failed, or handle non-shell tasks — like asking for a pasta recipe — straight from the terminal.
• GPT-4 support: If you have access to GPT-4, run $ butterfish shell -m gpt-4.
• Capital-letter prompts: Start a command with a capital letter to trigger AI suggestions and assistance.
• Customization and contribution: Edit prompt wrappers to personalize your experience, and contribute to the open-source project.

Who is Butterfish Shell for?

Developers, software engineers, data scientists, IT professionals, and tech enthusiasts who want AI assistance without leaving the terminal.

How to use Butterfish Shell

1. Install: On macOS, use Homebrew with brew install bakks/bakks/butterfish. On Linux, run go install github.com/bakks/butterfish/cmd/butterfish@latest.
2. Start the shell: Launch Butterfish by typing butterfish shell.
3. Work as usual: Keep using your shell normally; begin a command with a capital letter to get AI help.
4. Ask and automate: Request a command for a specific task, ask why a command didn’t work, or switch to Goal Mode to let the AI handle tasks automatically.