Codex CLI — AI Coding in Your Terminal

Installation & Startup {#installation}

### One-liner install script ``bash curl -fsSL https://codex.sh/install | sh `

### Install via npm `bash npm install -g @openai/codex `

### Install via Homebrew (macOS) `bash brew install --cask codex `

### Verify installation `bash codex --version `

### Start interactive mode `bash codex `

### Launch web UI `bash codex app `

### Single prompt `bash codex "Write a Python Fibonacci function" `

### Download from GitHub Release `bash # Visit https://github.com/openai/codex/releases to download platform-specific binaries `

Chat Sessions {#chat-sessions}

### View help `bash /help `

### Clear session `bash /clear `

### View diff `bash /diff `

### Undo changes `bash /undo `

### Exit `bash /exit `

### Specify model `bash codex --model o4-mini `

Code Development {#code-development}

### Code review `bash /review `

### Auto-fix `bash /fix `

### Run tests `bash /test `

### Commit code `bash /commit `

### Generate tests `bash codex "Generate pytest tests for functions in utils.py" `

### Refactor code `bash codex "Refactor main.py to extract database logic into a separate module" `

### Generate documentation `bash codex "Generate Google-style docstrings for all public functions in project/" `

Configuration & Environment {#configuration}

### CODEX.md project config `markdown # .codex configuration — create CODEX.md in project root

Instructions

### API Key authentication `bash export OPENAI_API_KEY="sk-xxxx" codex `

### ChatGPT sign-in `bash codex app # Sign in with your ChatGPT account in the browser that opens `

### Check version `bash codex --version `

### Config file location `bash # macOS: ~/Library/Application Support/codex/ # Linux: ~/.config/codex/ # Env variable: CODEX_DIR ``