tmux Session Control

Control tmux sessions by sending keystrokes and reading output. Essential for managing Claude Code sessions.

When to Use

✅ USE this skill when:

Monitoring Claude/Codex sessions in tmux
Sending input to interactive terminal applications
Scraping output from long-running processes in tmux
Navigating tmux panes/windows programmatically
Checking on background work in existing sessions

When NOT to Use

❌ DON'T use this skill when:

Running one-off shell commands → use exec tool directly
Starting new background processes → use exec with background:true
Non-interactive scripts → use exec tool
The process isn't in tmux
You need to create a new tmux session → use exec with tmux new-session

Example Sessions

Session Purpose

shared

Primary interactive session

worker-2

worker-8

Parallel worker sessions

Common Commands

List Sessions

tmux list-sessions tmux ls

Capture Output

Last 20 lines of pane

tmux capture-pane -t shared -p | tail -20

Entire scrollback

tmux capture-pane -t shared -p -S -

Specific pane in window

tmux capture-pane -t shared:0.0 -p

Send Keys

Send text (doesn't press Enter)

tmux send-keys -t shared "hello"

Send text + Enter

tmux send-keys -t shared "y" Enter

Send special keys

tmux send-keys -t shared Enter tmux send-keys -t shared Escape tmux send-keys -t shared C-c # Ctrl+C tmux send-keys -t shared C-d # Ctrl+D (EOF) tmux send-keys -t shared C-z # Ctrl+Z (suspend)

Window/Pane Navigation

Select window

tmux select-window -t shared:0

Select pane

tmux select-pane -t shared:0.1

List windows

tmux list-windows -t shared

Session Management

Create new session

tmux new-session -d -s newsession

Kill session

tmux kill-session -t sessionname

Rename session

tmux rename-session -t old new

Sending Input Safely

For interactive TUIs (Claude Code, Codex, etc.), split text and Enter into separate sends to avoid paste/multiline edge cases:

tmux send-keys -t shared -l -- "Please apply the patch in src/foo.ts" sleep 0.1 tmux send-keys -t shared Enter

Claude Code Session Patterns

Check if Session Needs Input

Look for prompts

Approve Claude Code Prompt

Send 'y' and Enter

tmux send-keys -t worker-3 'y' Enter

Or select numbered option

tmux send-keys -t worker-3 '2' Enter

Check All Sessions Status

for s in shared worker-2 worker-3 worker-4 worker-5 worker-6 worker-7 worker-8; do echo "=== $s ===" tmux capture-pane -t $s -p 2>/dev/null | tail -5 done

Send Task to Session

tmux send-keys -t worker-4 "Fix the bug in auth.js" Enter

Notes

Use capture-pane -p to print to stdout (essential for scripting)
-S - captures entire scrollback history
Target format: session:window.pane (e.g., shared:0.0 )
Sessions persist across SSH disconnects

tmux

Safety Notice

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