tmux - Control Interactive CLI Tools

Use tmux to run and control interactive programs (VisiData, PDB, mysql, psql, etc.) programmatically.

The Pattern

Every interactive tool uses the same 3-step pattern:

Step 1: Create Session

SOCKET="/tmp/claude-tmux-sockets/claude.sock"
SESSION="my-session"

mkdir -p /tmp/claude-tmux-sockets
tmux -S "$SOCKET" new -d -s "$SESSION" "your_command_here"
sleep 1

Step 2: Discover Pane (Always :1.1)

# Check what the pane target is (always :1.1 in our setup)
tmux -S "$SOCKET" list-panes -a -F '#{session_name}:#{window_index}.#{pane_index}'
# Output: my-session:1.1

# Use this pane target for all commands
PANE="my-session:1.1"

Step 3: Send Commands & Capture

# Send keystrokes
tmux -S "$SOCKET" send-keys -t "$PANE" "your_command" Enter
sleep 1

# Capture output
tmux -S "$SOCKET" capture-pane -p -J -t "$PANE" -S -20

# Cleanup when done
tmux -S "$SOCKET" kill-session -t "$SESSION"

Complete Examples

VisiData

SOCKET="/tmp/claude-tmux-sockets/claude.sock"
SESSION="vd-session"
PANE="vd-session:1.1"

mkdir -p /tmp/claude-tmux-sockets
tmux -S "$SOCKET" new -d -s "$SESSION" "vd data.csv"
sleep 2

# Navigate to bottom
tmux -S "$SOCKET" send-keys -t "$PANE" "G"
sleep 1

# Capture view
tmux -S "$SOCKET" capture-pane -p -J -t "$PANE" -S -20

# Quit
tmux -S "$SOCKET" send-keys -t "$PANE" "gq"
tmux -S "$SOCKET" kill-session -t "$SESSION"

PDB (Python Debugger)

SOCKET="/tmp/claude-tmux-sockets/claude.sock"
SESSION="pdb-session"
PANE="pdb-session:1.1"

mkdir -p /tmp/claude-tmux-sockets
tmux -S "$SOCKET" new -d -s "$SESSION"
sleep 1

# Start PDB
tmux -S "$SOCKET" send-keys -t "$PANE" "python -m pdb script.py" Enter
sleep 1

# Set breakpoint
tmux -S "$SOCKET" send-keys -t "$PANE" "break 10" Enter
tmux -S "$SOCKET" send-keys -t "$PANE" "continue" Enter
sleep 1

# Inspect variables
tmux -S "$SOCKET" send-keys -t "$PANE" "p my_variable" Enter
sleep 0.5

# Capture
tmux -S "$SOCKET" capture-pane -p -J -t "$PANE" -S -20

# Quit
tmux -S "$SOCKET" send-keys -t "$PANE" "quit" Enter
tmux -S "$SOCKET" kill-session -t "$SESSION"

Database Shell (psql, mysql, sqlite3)

SOCKET="/tmp/claude-tmux-sockets/claude.sock"
SESSION="db-session"
PANE="db-session:1.1"

mkdir -p /tmp/claude-tmux-sockets
tmux -S "$SOCKET" new -d -s "$SESSION"
sleep 1

# Start database
tmux -S "$SOCKET" send-keys -t "$PANE" "sqlite3 mydb.db" Enter
sleep 1

# Run query
tmux -S "$SOCKET" send-keys -t "$PANE" "SELECT * FROM users LIMIT 5;" Enter
sleep 0.5

# Capture results
tmux -S "$SOCKET" capture-pane -p -J -t "$PANE" -S -20

# Exit
tmux -S "$SOCKET" send-keys -t "$PANE" ".quit" Enter
tmux -S "$SOCKET" kill-session -t "$SESSION"

Critical Rules

1. Pane is Always :1.1

In our setup, the pane target is always session-name:1.1, not :0.0.

Don't guess - verify once:

tmux -S "$SOCKET" list-panes -a
# Shows: session-name:1.1: [80x24] ...

2. Never Use Command Substitution

❌ WRONG - Causes parse error:

PANE=$(tmux list-panes ...)  # parse error near '('

✅ CORRECT - Hardcode the pane:

PANE="my-session:1.1"  # Always :1.1 in our setup

3. Tell User How to Monitor

Always print this after creating a session:

echo "Monitor with: tmux -S \"$SOCKET\" attach -t $SESSION"
echo "Detach with: Ctrl+b d"

4. Wait After Commands

Interactive programs need time to process:

tmux send-keys -t "$PANE" "command" Enter
sleep 1  # Give it time to execute
tmux capture-pane -p -J -t "$PANE" -S -20

User Monitoring

Users can attach to watch:

# In their terminal
tmux -S "/tmp/claude-tmux-sockets/claude.sock" attach -t session-name

# Detach without quitting: Ctrl+b d

Cleanup

# Kill specific session
tmux -S "$SOCKET" kill-session -t "$SESSION"

# Kill all sessions
tmux -S "$SOCKET" kill-server

That's It

Three steps for any interactive tool:

1. Create session with tool running
2. Use pane :1.1
3. Send keys, capture output

Works the same for VisiData, PDB, psql, mysql, Python REPL, node, etc.