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.