/tmux-terminal

name: tmux-terminal
description: Interactive terminal control via tmux for TUI apps, prompts, and long-running CLI workflows.
hats: [developer, qa_tester]
metadata:
  internal: true

tmux-terminal

Overview

Use tmux to drive interactive terminal sessions, including TUI workflows like `ralph-tui`. tmux lets you send keystrokes, capture screen output, and keep processes running between steps.

When to Use

• Testing `ralph-tui` or any interactive CLI prompts
• Managing long-running processes (web server, loops, watch mode)
• Capturing live terminal output for QA reports
• Interacting with applications that redraw the screen

Prerequisites

• `tmux` installed (pre-installed on macOS)

Verify:

tmux -V

Core Commands

Create a detached session:

tmux new-session -d -s <name>

Send commands (append Enter to execute):

tmux send-keys -t <name> "<command>" Enter

Capture screen output:

tmux capture-pane -t <name> -p

Kill session when done:

tmux kill-session -t <name>

Special Keys

Use `send-keys` with key names:

• `Enter`
• `C-c` (Ctrl-C)
• `C-d` (Ctrl-D)
• `Tab`
• `Escape`
• `Up`, `Down`, `Left`, `Right`

Examples:

tmux send-keys -t <name> Up
tmux send-keys -t <name> C-c

TUI Interaction Patterns

Start ralph-tui

tmux new-session -d -s ralph-tui
tmux send-keys -t ralph-tui "cargo run -p ralph-tui" Enter

Navigate in TUI

tmux send-keys -t ralph-tui Down
tmux send-keys -t ralph-tui Enter

Capture and parse the screen

tmux capture-pane -t ralph-tui -p -S -200

Use `-S -200` to capture the last 200 lines when the screen is noisy.

Long-Running Process Management

• Start servers or loops in a tmux session to keep them alive.
• Use `capture-pane` to confirm health (look for "listening" or "ready" text).
• Stop cleanly with `C-c` then `kill-session`.

Example:

tmux new-session -d -s ralph-web
tmux send-keys -t ralph-web "cargo run -p ralph-cli -- web" Enter
tmux capture-pane -t ralph-web -p | rg -n "listening|ready"
tmux send-keys -t ralph-web C-c
tmux kill-session -t ralph-web

Notes

• Keep session names short and unique.
• Always clean up sessions to avoid leaking background processes.
• If output looks empty, wait briefly and capture again.