tmux

Terminal multiplexer for background processes, output capture, and session management.

Quick Reference

Command Description

tmux new -d -s name 'cmd'

Run command in background session

tmux capture-pane -t name -p

Capture output from session

tmux send-keys -t name 'text' Enter

Send input to session

tmux kill-session -t name

Terminate session

tmux ls

List all sessions

tmux has -t name

Check if session exists

Running Background Processes

Run command in new detached session

tmux new-session -d -s myserver 'python -m http.server 8080'

With specific working directory

tmux new-session -d -s build -c /path/to/project 'make build'

Keep session alive after command completes

tmux new-session -d -s task 'command; exec bash'

Run only if session doesn't exist

tmux has -t myserver || tmux new-session -d -s myserver 'command'

Capturing Output

Capture visible output

tmux capture-pane -t mysession -p

Capture entire scrollback history

tmux capture-pane -t mysession -p -S -

Capture last N lines

tmux capture-pane -t mysession -p -S -100

Save to file

tmux capture-pane -t mysession -p > output.txt

Capture with escape sequences (colors)

tmux capture-pane -t mysession -p -e

Sending Input

Send text and Enter

tmux send-keys -t mysession 'echo hello' Enter

Send without Enter

tmux send-keys -t mysession 'some-text'

Send Ctrl+C

tmux send-keys -t mysession C-c

Session Management

List sessions

tmux list-sessions tmux ls

Kill specific session

tmux kill-session -t myserver

Kill all sessions

tmux kill-server

Check if session exists

tmux has -t mysession

Wait for Completion

Signal completion from command

tmux new-session -d -s job 'command; tmux wait-for -S job-done'

Wait for signal

tmux wait-for job-done

Common Patterns

Development Servers

tmux new-session -d -s backend 'bun run backend' tmux new-session -d -s frontend 'bun run frontend' tmux new-session -d -s tests 'vitest --watch'

Run and Capture Output

tmux new-session -d -s job 'command' sleep 0.5 output=$(tmux capture-pane -t job -p) echo "$output"

Conditional Session

tmux has -t myserver || tmux new-session -d -s myserver 'command'

Cleanup

tmux kill-session -t backend tmux kill-session -t frontend tmux kill-server # Kill all

Tips

• Use tmux new-session -d for background processes

• Use tmux capture-pane -p -S - for full scrollback

• Use tmux has -t name to check session existence

• Use tmux kill-server to clean up all sessions

• Use -c /path to set working directory

• Use exec bash to keep session alive after command