gemini-cli/docs/cli/index.md

# Gemini CLI

Within Gemini CLI, `packages/cli` is the frontend for users to send and receive prompts with the Gemini AI model and its associated tools. For a general overview of Gemini CLI, see the [main documentation page](../index.md).

## Navigating this section

- **[Authentication](./authentication.md):** A guide to setting up authentication with Google's AI services.
- **[Commands](./commands.md):** A reference for Gemini CLI commands (e.g., `/help`, `/tools`, `/theme`).
- **[Configuration](./configuration.md):** A guide to tailoring Gemini CLI behavior using configuration files.
- **[Enterprise](./enterprise.md):** A guide to enterprise configuration.
- **[Token Caching](./token-caching.md):** Optimize API costs through token caching.
- **[Themes](./themes.md)**: A guide to customizing the CLI's appearance with different themes.
- **[Tutorials](tutorials.md)**: A tutorial showing how to use Gemini CLI to automate a development task.

## Non-interactive mode

Gemini CLI can be run in a non-interactive mode, which is useful for scripting and automation. In this mode, you pipe input to the CLI, it executes the command, and then it exits.

The following example pipes a command to Gemini CLI from your terminal:

```bash
echo "What is fine tuning?" | gemini
```

Gemini CLI executes the command and prints the output to your terminal. Note that you can achieve the same behavior by using the `--prompt` or `-p` flag. For example:

```bash
gemini -p "What is fine tuning?"
```

For non-interactive usage with structured output, use the `--output-format json` flag for scripting and automation.

Get structured JSON output for scripting:

```bash
gemini -p "What is fine tuning?" --output-format json
# Output:
# {
#   "response": "Fine tuning is...",
#   "stats": {
#     "models": { "gemini-2.5-flash": { "tokens": {"total": 45} } }
#   },
#   "error": null
# }
```