Using Gemini CLI as an adhoc commandline question answerer

Google’s Gemini CLI is command line, context aware assistant: it looks at your current directory, tools, and tries to make helpful suggestions. Here I go over how I was able to somewhat trim it down to a simple adhoc helper. I just type ? "How do I..." and get an answer.

What gemini does

By default, gemini runs in an interactive mode. It starts up a text interface with a little text-input-box, where you can ask questions, it provides answers, and you carry on the chat there.

What I want

I’m not so interested in this mode, I would prefer that this tool answer my question and get out of my way. And I’m really keen on using ? as the invoker because it’s so short and easy to type.

$ ? "How do I list all files in a directory?"

You can use the `ls` command to list files in a directory!

Gemini CLI’s non interactive mode

To that end, the Gemini CLI takes a positional prompt which is the question being asked. It can be passed in two ways:

gemini "How do I list all files in a directory?"
# or
echo "How do I list all files in a directory?" | gemini -

This positional prompt is basically the non-interactive mode, which is what I’m interested in.

Unfortunately, out of the box, I found its defaults to be somewhat unsafe. Gemini CLI comes with a security risk: it has access to some tools already, and those tools execute even when using the non interactive mode, without asking. A decision probably made to make it more convenient.

How I configured it

Gemini can work off a settings file, located at ~/.gemini/settings.json, in which I minimised its core tools:

$ cat ~/.gemini/settings.json

{
  "security": {
    "auth": {
      "selectedType": "oauth-personal"
    }
  },
  "ui": {
    "theme": "Dracula"
  },
  "tools": {
    "autoAccept": false,
    "core": []
  },
  "mcp": {
    "allowed": []
  },
  "telemetry": {
    "enabled": false,
    "target": "local",
    "outfile": "/dev/null"
  }
}

Further, it can take a ~/.gemini/GEMINI.md file which gives it the context for the questions. I told it to be simple:

$ cat ~/.gemini/GEMINI.md

You will act as an assistant that answers questions about how to perform actions in a Linux commandline environment. 
When asked a question, generate a sample command that can accomplish what the user is asking for. 
If the question is not related to Linux, answer the question in brief.
Important: NEVER offer to run any tools.

And finally, to be able to use the ? command, I added this to my .bashrc:

? () {
    gemini "$*"
}

That’s it, the results were just what I wanted: