Using Tmux

Using tmux for Interactive Commands

Persona: Terminal automation expert - enables programmatic control of interactive applications.

When NOT to Use

• Simple non-interactive commands (use Bash directly)
• Commands that accept stdin redirection
• One-shot commands that exit immediately

Quick Reference

Core Pattern

# 1. Create detached session
tmux new-session -d -s mysession vim file.txt

# 2. Wait for init
sleep 0.3

# 3. Send keys (Enter, Escape are tmux key names, not \n)
tmux send-keys -t mysession 'iHello World' Escape ':wq' Enter

# 4. Capture output
tmux capture-pane -t mysession -p

# 5. Clean up
tmux kill-session -t mysession

Special Keys

Common Patterns

Interactive Git Rebase

tmux new-session -d -s rebase -c /path/to/repo git rebase -i HEAD~3
sleep 0.5
tmux capture-pane -t rebase -p  # See editor
tmux send-keys -t rebase 'cwsquash' Escape 'j' 'cwsquash' Escape ':wq' Enter
tmux capture-pane -t rebase -p  # See result
tmux kill-session -t rebase

Git Add Patch Mode

tmux new-session -d -s patch -c /path/to/repo git add -p
sleep 0.3
tmux capture-pane -t patch -p  # See hunk
tmux send-keys -t patch 'y'    # Stage this hunk
tmux capture-pane -t patch -p  # See next
tmux send-keys -t patch 'n'    # Skip this one
tmux send-keys -t patch 'q'    # Quit
tmux kill-session -t patch

Python REPL

tmux new-session -d -s py python3
sleep 0.2
tmux send-keys -t py 'import math' Enter
tmux send-keys -t py 'print(math.pi)' Enter
tmux capture-pane -t py -p
tmux send-keys -t py 'exit()' Enter
tmux kill-session -t py

Vim Edit

tmux new-session -d -s vim vim /tmp/test.txt
sleep 0.3
tmux send-keys -t vim 'i' 'New content here' Escape ':wq' Enter
tmux kill-session -t vim 2>/dev/null

Common Mistakes

Should NOT Attempt

• Using for non-interactive commands (wasteful overhead)
• Sending shell escape sequences (\n, \t) instead of tmux key names
• Forgetting cleanup (orphaned sessions accumulate)
• Capturing immediately without sleep (blank output)

Failure Behavior

If tmux commands fail:

1. Check if tmux is installed: which tmux
2. Check if session exists: tmux has-session -t NAME
3. List all sessions: tmux list-sessions
4. Kill stuck session: tmux kill-session -t NAME

Escalation