Remote Input Simulation for CLI Applications (Beyond Visualization)

[DaKoTaGeorgia]

I'm exploring ways to introduce remote input into a CLI application, specifically aiming to simulate the behavior of typing text into the CLI and pressing Enter, but from a remote source. The goal is to trigger actions in the CLI application (for example, to interact with Gemini models) just as if the input were entered manually.
Currently, the application processes input received via stdin when a user types something and presses Enter. I'm looking for methods to replicate this behavior remotely, without relying on visual screen sharing or similar visualization-based techniques.
In essence, I need a way to programmatically "inject" text and Enter key presses into the CLI application's input stream from a remote source.
Are there any recommended approaches or existing libraries/tools that would facilitate this type of remote input simulation? I'm open to various methods, including (but not limited to):
Using pipes or other inter-process communication (IPC) mechanisms.
Employing a virtual terminal (pty) and writing to its input.
Leveraging specific language/platform features for input redirection or simulation.
Any suggestions or insights would be greatly appreciated.

[daniat707]

Hi there. Great question. I haven't done that before, but I did some research and maybe one good way to simulate remote input (like typing and pressing Enter) into a CLI app is by using a pseudo-terminal (PTY). It acts like a real terminal, so your app thinks someone is typing:

Example in Python:

import pty
import os

pid, fd = pty.fork()
if pid == 0:
    os.execvp("your_cli_app", ["your_cli_app"])
else:
    os.write(fd, b"your input here\n")

You can also try:

• Named pipes (FIFO): mkfifo input.pipe && your_cli_app < input.pipe, then echo "text" > input.pipe from elsewhere.

• SSH remote injection: ssh user@host 'echo "text" | your_cli_app'

• Or tools like pexpect (Python) or node-pty (Node.js) for more control.

[Manamama]

Somewhat related: #2841, the first show and tell item

[Manamama]

Why not just gemini -p instead? You can then pipe anything.

[daniat707]

You're right. If you wanted to send text from a script or remote source, gemini -p is the simplest approach. But if you need multiple prompts/responses, maybe PTY might be helpful.

[Manamama]

Random thoughts on 📲: plus https://www.langchain.com, plus... just MCP out of Gemini ♊ CLI... Oh, speaking of which: sugyan/claude-code-webui#188, almost ready.

See also the new 🛣️ roadmap #4226 here.