tmux

tmux & tmuxp Skill

Create, edit, debug, and optimize tmux sessions via tmuxp YAML configurations.

Quick Decisions

Session Name Rules

tmux session names cannot contain periods (.) or colons (:).

Common pitfall: using ${USER} in session_name when the username contains periods (e.g., first.last). Always use a static name or sanitize:

# BAD - breaks if USER contains periods
session_name: ${USER}-project

# GOOD - static name
session_name: project-dev

# GOOD - sanitized
session_name: project-${USER//\./-}

Configuration Structure

session_name: project-name          # Required. No periods or colons.
start_directory: ~/Projects/foo     # Default working dir for all windows
environment:                        # Session-wide env vars
  PROJECT_ROOT: ~/Projects/foo
suppress_history: false             # Whether to hide commands from shell history

before_script: |                    # Runs before session creation. Exit 1 = abort.
  echo "Validating..."

after_script: |                     # Runs after session is destroyed
  echo "Cleaning up..."

windows:
  - window_name: editor             # Window identifier
    focus: true                     # Make this the active window on load
    layout: main-vertical           # Pane layout
    start_directory: ~/Projects/foo/src
    options:
      main-pane-width: 70%          # Layout-specific options
    shell_command_before:            # Runs in ALL panes before pane commands
      - source ~/.zshrc
    panes:
      - focus: true                 # Active pane within window
        shell_command:
          - vim .
      - shell_command:
          - npm test -- --watch