tmux_skill

Overview

This skill shows how to use tmux to spawn and manage background processes, inspect their output, and clean them up. It provides a concise pattern for creating detached windows, sending commands, capturing visible output or full scrollback, and interacting with running tasks. Use it to run servers, watchers, or long-running jobs without blocking your main shell.

How this skill works

The skill uses tmux windows (detached by default) as isolated execution contexts. Create a new window with tmux new-window -n "NAME" -d, send the command with tmux send-keys -t "NAME" "CMD" C-m, and read output using tmux capture-pane -p -t "NAME" or tmux capture-pane -p -S - -t "NAME" for full history. You can interrupt a process with tmux send-keys -t "NAME" C-c and remove the window with tmux kill-window -t "NAME".

When to use it

• Running development servers or background daemons alongside an interactive session
• Starting long builds, tests, or tasks that should persist if your terminal disconnects
• Capturing logs or debugging output without attaching to the tmux session
• Orchestrating multiple independent processes that need distinct consoles
• Quickly restarting or killing a background process without searching PIDs

Best practices

• Name windows clearly (e.g., server-log, watcher, build) to make targeting and inspection simple
• Create windows detached (-d) so the main workflow remains uninterrupted
• Use capture-pane -p -S - to get full scrollback when logs may have scrolled off-screen
• Chain tmux commands with ';' in one invocation to avoid race conditions and simplify scripts
• Always verify you are inside tmux (echo $TMUX) before running tmux-targeted commands

Example use cases

• Start a React dev server in a detached tmux window: new-window -n "web" -d; send-keys -t "web" "npm start" C-m
• Run a file-watcher and inspect logs without switching panes by capturing the pane output
• Launch a long test suite in its own window and kill it if it hangs using send-keys C-c
• Keep multiple microservices running in separate windows for local integration testing
• Automate startup: script that creates windows, launches services, and captures their initial logs