Tmux Sessions

Overview

Use tmux to manage background processes, run dev servers, and execute parallel tasks without blocking the main terminal.

Quick Reference

Create and manage sessions

# New named session
tmux new-session -d -s dev-server

# List sessions
tmux list-sessions

# Attach to session
tmux attach -t dev-server

# Kill session
tmux kill-session -t dev-server

Send commands to a session

# Run a command in a detached session
tmux send-keys -t dev-server 'npm run dev' Enter

# Send Ctrl+C to stop
tmux send-keys -t dev-server C-c

Read session output

# Capture last 200 lines of output
tmux capture-pane -p -t dev-server -S -200

Common Patterns

Dev Server in Background

tmux new-session -d -s server
tmux send-keys -t server 'npm run dev' Enter
# ... work on other things ...
tmux capture-pane -p -t server -S -50  # Check logs
tmux send-keys -t server C-c           # Stop server
tmux kill-session -t server

Parallel Test Runs

tmux new-session -d -s test-unit
tmux new-session -d -s test-e2e
tmux send-keys -t test-unit 'npm run test:unit' Enter
tmux send-keys -t test-e2e 'npm run test:e2e' Enter
# Check results
tmux capture-pane -p -t test-unit -S -20
tmux capture-pane -p -t test-e2e -S -20

Watch Build Output

tmux new-session -d -s build
tmux send-keys -t build 'npm run build:watch' Enter
# Periodically check
tmux capture-pane -p -t build -S -10

Tips

• Always use -d (detached) when creating sessions from scripts
• Use descriptive session names: dev-server, test-runner, build-watch
• Clean up sessions when done: tmux kill-server removes all
• For interactive TUI apps, send text and Enter separately with a small delay:

  tmux send-keys -t target -l "command" && sleep 0.1 && tmux send-keys -t target Enter
  

• Capture output with -S -200 to get enough context (last 200 lines)