Tmux

Overview

Use tmux to spawn background processes, inspect output, and control long-running tasks in dedicated windows. Prefer this skill when starting dev servers, watchers, or builds that must keep running while continuing other work.

Verify Environment

Confirm tmux is available before issuing commands.

bash

echo $TMUX

If empty, avoid tmux commands and run processes in the foreground instead.

List current windows for visibility before creating new ones.

bash

tmux list-windows

Spawn a Background Process

Create a detached window with a descriptive name.

bash

tmux new-window -n "server-log" -d

Send the command to that window and execute it.

bash

tmux send-keys -t "server-log" "npm start" C-m

Replace the window name and command with task-specific values.

Inspect Output

Capture the visible screen output for quick checks.

bash

tmux capture-pane -p -t "server-log"

Capture full scrollback history when output may have scrolled off.

bash

tmux capture-pane -p -S - -t "server-log"

Control the Process

Send an interrupt (Ctrl+C) to stop the running process.

bash

tmux send-keys -t "server-log" C-c

Kill the entire window when cleanup is needed.

bash

tmux kill-window -t "server-log"

Chain Commands

Chain tmux commands in a single invocation when efficiency matters.

bash

tmux new-window -n "server-log" -d ';' send-keys -t "server-log" "npm start" C-m

Quick Pattern

Use this three-step flow for most tasks.

•tmux new-window -n "ID" -d
•tmux send-keys -t "ID" "CMD" C-m
•tmux capture-pane -p -t "ID"