Running Interactive Commands With Tmux

Using tmux for Interactive Commands

Overview

Interactive CLI tools (vim, interactive git rebase, REPLs, etc.) cannot be controlled through standard bash because they require a real terminal. tmux provides detached sessions that can be controlled programmatically via send-keys and capture-pane.

When to Use

Use tmux when:

• Running vim, nano, or other text editors programmatically
• Controlling interactive REPLs (Python, Node, etc.)
• Handling interactive git commands (git rebase -i, git add -p)
• Working with full-screen terminal apps (htop, etc.)
• Commands that require terminal control codes or readline

Don't use for:

• Simple non-interactive commands (use regular Bash tool)
• Commands that accept input via stdin redirection
• One-shot commands that don't need interaction

Quick Reference

Core Pattern

Before (Won't Work)

# This hangs because vim expects interactive terminal
bash -c "vim file.txt"

After (Works)

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

# Send commands (Enter, Escape are tmux key names)
tmux send-keys -t edit_session 'i' 'Hello World' Escape ':wq' Enter

# Capture what's on screen
tmux capture-pane -t edit_session -p

# Clean up
tmux kill-session -t edit_session

Implementation

Basic Workflow

1. Create detached session with the interactive command
2. Wait briefly for initialization (100-500ms depending on command)
3. Send input using send-keys (can send special keys like Enter, Escape)
4. Capture output using capture-pane -p to see current screen state
5. Repeat steps 3-4 as needed
6. Terminate session when done

Special Keys

Common tmux key names:

• Enter - Return/newline
• Escape - ESC key
• C-c - Ctrl+C
• C-x - Ctrl+X
• Up, Down, Left, Right - Arrow keys
• Space - Space bar
• BSpace - Backspace

Working Directory

Specify working directory when creating session:

tmux new-session -d -s git_session -c /path/to/repo git rebase -i HEAD~3

Helper Wrapper

For easier use, see /home/jesse/git/interactive-command/tmux-wrapper.sh:

# Start session
/path/to/tmux-wrapper.sh start <session-name> <command> [args...]

# Send input
/path/to/tmux-wrapper.sh send <session-name> 'text' Enter

# Capture current state
/path/to/tmux-wrapper.sh capture <session-name>

# Stop
/path/to/tmux-wrapper.sh stop <session-name>

Common Patterns

Python REPL

tmux new-session -d -s python python3 -i
tmux send-keys -t python 'import math' Enter
tmux send-keys -t python 'print(math.pi)' Enter
tmux capture-pane -t python -p  # See output
tmux kill-session -t python

Vim Editing

tmux new-session -d -s vim vim /tmp/file.txt
sleep 0.3  # Wait for vim to start
tmux send-keys -t vim 'i' 'New content' Escape ':wq' Enter
# File is now saved

Interactive Git Rebase

tmux new-session -d -s rebase -c /repo/path git rebase -i HEAD~3
sleep 0.5
tmux capture-pane -t rebase -p  # See rebase editor
# Send commands to modify rebase instructions
tmux send-keys -t rebase 'Down' 'Home' 'squash' Escape
tmux send-keys -t rebase ':wq' Enter

Common Mistakes

Not Waiting After Session Start

Problem: Capturing immediately after new-session shows blank screen

Fix: Add brief sleep (100-500ms) before first capture

tmux new-session -d -s sess command
sleep 0.3  # Let command initialize
tmux capture-pane -t sess -p

Forgetting Enter Key

Problem: Commands typed but not executed

Fix: Explicitly send Enter

tmux send-keys -t sess 'print("hello")' Enter  # Note: Enter is separate argument

Using Wrong Key Names

Problem: tmux send-keys -t sess '\n' doesn't work

Fix: Use tmux key names: Enter, not \n

tmux send-keys -t sess 'text' Enter  # ✓
tmux send-keys -t sess 'text\n'      # ✗

Not Cleaning Up Sessions

Problem: Orphaned tmux sessions accumulate

Fix: Always kill sessions when done

tmux kill-session -t session_name
# Or check for existing: tmux has-session -t name 2>/dev/null

Progressive Details

For advanced patterns including Claude Code orchestration and remote monitoring protocols, see sections below.

Controlling Claude Code Sessions in tmux

The Two-Step Pattern (CRITICAL)

Claude Code running in tmux requires a two-step command pattern:

1. Queue the command: Send command with C-m (appears in prompt but doesn't execute)
2. Execute the command: Send C-m again (executes the queued command)

Example - Sending a Command to Claude Code:

# Step 1: Queue the command in the Claude Code prompt
tmux send-keys -t csv-import 'date -u +"%Y-%m-%d %H:%M:%S UTC"' C-m

# Step 2: Send Return to execute the queued command
tmux send-keys -t csv-import C-m

# Step 3: Monitor output after brief wait
sleep 3 && tmux capture-pane -t csv-import -p | tail -15

Launching Claude Code in tmux

Create a detached tmux session running Claude Code:

# Create tmux session with Claude Code
tmux new-session -d -s csv-import -c /path/to/project

# Send the Claude Code launch command (two steps)
tmux send-keys -t csv-import 'claude -p "your prompt here"' C-m
tmux send-keys -t csv-import C-m

# Monitor session startup
sleep 5 && tmux capture-pane -t csv-import -p | tail -30

Common Operations

Execute a prompt:

# Queue the command
tmux send-keys -t csv-import 'claude -p "analyze the codebase"' C-m

# Execute it
tmux send-keys -t csv-import C-m

# Monitor progress
sleep 2 && tmux capture-pane -t csv-import -p | tail -40

Send multi-line prompts (use heredoc in file, reference in command):

# Create prompt file first
cat > /tmp/prompt.txt <<'EOF'
Your detailed prompt here
with multiple lines
EOF

# Send command referencing file
tmux send-keys -t csv-import 'claude -p "$(cat /tmp/prompt.txt)"' C-m
tmux send-keys -t csv-import C-m

Monitor ongoing execution:

# Continuous monitoring (every 30 seconds)
while true; do
  echo "=== Status at $(date -u +"%H:%M:%S") ==="
  tmux capture-pane -t csv-import -p | tail -25
  sleep 30
done

Check if Claude Code is still active:

# Capture current state
tmux capture-pane -t csv-import -p | tail -20

# Look for indicators:
# - "Garnishing..." = processing
# - Fresh prompt = ready for next command
# - Error messages = needs attention

Critical Mistakes with Claude Code

❌ WRONG - Single C-m (command queued but not executed):

tmux send-keys -t csv-import 'date' C-m
# Command appears in prompt but doesn't run!

✅ CORRECT - Two-step pattern:

tmux send-keys -t csv-import 'date' C-m  # Queue
tmux send-keys -t csv-import C-m         # Execute

❌ WRONG - Using Enter instead of C-m:

tmux send-keys -t csv-import 'command' Enter Enter
# May not work consistently with Claude Code

✅ CORRECT - Use C-m for Return:

tmux send-keys -t csv-import 'command' C-m  # Queue
tmux send-keys -t csv-import C-m            # Execute

Workflow Example: CSV Processing Pipeline

# 1. Launch Claude Code session
tmux new-session -d -s csv-import -c /path/to/project
tmux send-keys -t csv-import 'claude' C-m
tmux send-keys -t csv-import C-m
sleep 5

# 2. Send initial processing command
tmux send-keys -t csv-import 'claude -p "Extract CSV rows 2-401"' C-m
tmux send-keys -t csv-import C-m

# 3. Monitor progress
sleep 30 && tmux capture-pane -t csv-import -p | tail -30

# 4. Send next step after completion
tmux send-keys -t csv-import 'claude -p "Transform to JSON"' C-m
tmux send-keys -t csv-import C-m

# 5. Continue monitoring
while tmux capture-pane -t csv-import -p | grep -q "Garnishing"; do
  echo "Still processing..."
  sleep 15
done
echo "Processing complete"

Troubleshooting Claude Code in tmux

Symptom: Command appears in prompt but doesn't execute

• Cause: Forgot second C-m
• Fix: Send additional tmux send-keys -t session-name C-m

Symptom: Can't see what's happening

• Cause: Capture timing issue
• Fix: Add sleep before capture, increase tail lines

sleep 3 && tmux capture-pane -t csv-import -p | tail -40

Symptom: Session becomes unresponsive

• Cause: Claude Code waiting for input or error state
• Fix: Capture full pane to see error, send C-c to interrupt

tmux capture-pane -t csv-import -p
tmux send-keys -t csv-import C-c  # Interrupt

Remote Orchestration Protocol for Claude Code Sessions

Overview

When orchestrating a Claude Code session running in tmux from another Claude Code instance, you need a systematic approach to monitor progress, detect issues, and guide execution.

Session State Detection

Parse capture-pane output to determine state:

Monitoring Cycle Protocol

Every monitoring cycle should:

1. Capture current state:

tmux capture-pane -t SESSION -p | tail -60

2. Detect session state from indicators above

3. Log to scratch pad with timestamp and findings

4. Take action based on state:

   • IDLE + pending tasks → Send nudge command
   • ERROR → Analyze and send recovery command
   • ACTIVE → Continue monitoring
   • LOW_CONTEXT → Prepare for context reset

Intervention Commands

Nudge idle session to continue:

# Simple continuation nudge
tmux send-keys -t SESSION 'continue with the next task in the plan' C-m
sleep 0.5
tmux send-keys -t SESSION C-m

Recovery from API error:

# Acknowledge error and retry
tmux send-keys -t SESSION 'The previous operation encountered an API error. Please retry the last step.' C-m
sleep 0.5
tmux send-keys -t SESSION C-m

Context compaction trigger:

# Tell session to compact and continue
tmux send-keys -t SESSION '/clear' C-m
sleep 2
tmux send-keys -t SESSION 'Resume execution of docs/plans/2025-11-25-full-csv-transformation.md from where we left off' C-m
sleep 0.5
tmux send-keys -t SESSION C-m

Progress check request:

# Ask for status update
tmux send-keys -t SESSION 'What is the current progress? Which batch/task are you on?' C-m
sleep 0.5
tmux send-keys -t SESSION C-m

Orchestrator Decision Tree

START MONITORING CYCLE
        │
        ▼
┌───────────────────┐
│ Capture pane      │
│ (last 60 lines)   │
└─────────┬─────────┘
          │
          ▼
┌───────────────────┐     ┌─────────────────┐
│ Is session IDLE?  │─YES─▶│ Check pending   │
│ ("> " at bottom)  │      │ tasks in output │
└─────────┬─────────┘      └────────┬────────┘
          │NO                       │
          ▼                         ▼
┌───────────────────┐     ┌─────────────────┐
│ Is there ERROR?   │─YES─▶│ Send recovery   │
│ (API/tool error)  │      │ command         │
└─────────┬─────────┘      └────────┬────────┘
          │NO                       │
          ▼                         │
┌───────────────────┐               │
│ Is context LOW?   │─YES─▶ Log warning, prepare /clear
│ (<15% remaining)  │               │
└─────────┬─────────┘               │
          │NO                       │
          ▼                         │
┌───────────────────┐               │
│ Session ACTIVE    │               │
│ Continue monitor  │◀──────────────┘
└───────────────────┘
          │
          ▼
    SLEEP 30-60s
          │
          ▼
    NEXT CYCLE

Long-Running Orchestration Pattern

For multi-hour workflows like CSV transformation:

# Orchestration scratch pad file
SCRATCH_PAD="/tmp/orchestration-$(date +%Y%m%d).md"
SESSION="eddy-csv-transform"

# Initialize scratch pad
echo "# Orchestration Log - $(date -u +"%Y-%m-%d %H:%M:%S UTC")" > $SCRATCH_PAD

# Monitoring loop
while true; do
  TIMESTAMP=$(date -u +"%Y-%m-%d %H:%M:%S UTC")
  OUTPUT=$(tmux capture-pane -t $SESSION -p | tail -60)

  # Log to scratch pad
  echo "" >> $SCRATCH_PAD
  echo "## Check: $TIMESTAMP" >> $SCRATCH_PAD
  echo '```' >> $SCRATCH_PAD
  echo "$OUTPUT" | tail -20 >> $SCRATCH_PAD
  echo '```' >> $SCRATCH_PAD

  # State detection
  if echo "$OUTPUT" | grep -q "API Error\|Error:"; then
    echo "**STATUS**: ERROR detected" >> $SCRATCH_PAD
    # Send recovery command
    tmux send-keys -t $SESSION 'retry the last operation that failed' C-m
    sleep 0.5
    tmux send-keys -t $SESSION C-m
    echo "**ACTION**: Sent retry command" >> $SCRATCH_PAD

  elif echo "$OUTPUT" | grep -q "^> $" | tail -1; then
    # Check if truly idle (prompt visible, no activity)
    if echo "$OUTPUT" | grep -q "☐"; then
      echo "**STATUS**: IDLE with pending tasks" >> $SCRATCH_PAD
      tmux send-keys -t $SESSION 'continue with the next pending task' C-m
      sleep 0.5
      tmux send-keys -t $SESSION C-m
      echo "**ACTION**: Sent continuation nudge" >> $SCRATCH_PAD
    fi

  elif echo "$OUTPUT" | grep -q "Context left.*[0-9]%"; then
    CONTEXT_PCT=$(echo "$OUTPUT" | grep -o "Context left.*[0-9]*%" | grep -o "[0-9]*")
    if [ "$CONTEXT_PCT" -lt 15 ]; then
      echo "**STATUS**: LOW CONTEXT ($CONTEXT_PCT%)" >> $SCRATCH_PAD
      echo "**WARNING**: May need /clear soon" >> $SCRATCH_PAD
    fi
  else
    echo "**STATUS**: ACTIVE/PROCESSING" >> $SCRATCH_PAD
  fi

  # Sleep before next check
  sleep 45
done

Sub-Agent Orchestration Pattern

When using a sub-agent to monitor remotely:

Task(
    description="Monitor and orchestrate CSV transformation",
    prompt="""You are orchestrating a Claude Code session running in tmux session 'eddy-csv-transform'.

**YOUR MISSION**: Continuously monitor the session and guide it to completion of the full CSV transformation plan.

**MONITORING PROTOCOL**:
1. Capture current state: `tmux capture-pane -t eddy-csv-transform -p | tail -60`
2. Analyze state indicators (IDLE, ACTIVE, ERROR, LOW_CONTEXT)
3. Log findings to your scratch pad
4. Take appropriate action if needed
5. Sleep 45 seconds
6. REPEAT until all 20 batches complete

**STATE INDICATORS**:
- `> ` with no activity = IDLE, may need nudge
- `☐` unchecked = pending tasks
- `☒` checked = completed tasks
- `API Error` = needs recovery
- `Context left: X%` where X<15 = needs /clear

**INTERVENTION COMMANDS**:
- Nudge: `tmux send-keys -t eddy-csv-transform 'continue' C-m && sleep 0.5 && tmux send-keys -t eddy-csv-transform C-m`
- Recovery: `tmux send-keys -t eddy-csv-transform 'retry' C-m && sleep 0.5 && tmux send-keys -t eddy-csv-transform C-m`

**SUCCESS CRITERIA**:
- All 20 batches transformed, QA'd, and imported
- 1,916 universities in database with v3.9 schema
- PROGRESS.md shows all batches complete

**NEVER STOP** monitoring until the mission is complete or user intervenes.""",
    subagent_type="general-purpose"
)

Health Check Commands

Quick status check:

# One-liner status
tmux capture-pane -t SESSION -p | tail -5

Full diagnostic:

# Complete session dump
tmux capture-pane -t SESSION -p -S -1000 > /tmp/session-dump.txt

Check if session exists:

tmux has-session -t SESSION 2>/dev/null && echo "EXISTS" || echo "NOT FOUND"

Recovery Scenarios

Session crashed/closed:

# Recreate session and resume
tmux new-session -d -s SESSION -c /path/to/project
tmux send-keys -t SESSION 'claude' C-m
sleep 3
tmux send-keys -t SESSION C-m
sleep 5
tmux send-keys -t SESSION 'Resume execution of the plan from where we left off' C-m
tmux send-keys -t SESSION C-m

Session stuck on permission prompt:

# Press 'y' to accept
tmux send-keys -t SESSION 'y' C-m

Session needs user attention:

# Check what it's asking for
tmux capture-pane -t SESSION -p | tail -20
# Respond accordingly

Real-World Impact

• Enables programmatic control of vim/nano for file editing
• Allows automation of interactive git workflows (rebase, add -p)
• Makes REPL-based testing/debugging possible
• Unblocks any tool that requires terminal interaction
• Enables orchestrating Claude Code sessions from another Claude Code instance
• Remote monitoring protocol for long-running multi-hour workflows
• Automatic error recovery and continuation nudging
• No need to build custom PTY management - tmux handles it all