CaffeinateCLI

• caffeinate command

  • Overview

    • Built-in macOS command-line utility that prevents the system from sleeping
    • Part of the macOS system since OS X Mountain Lion (10.8)
    • Operates at the system level, more powerful than GUI alternatives
    • Note: This is different from CaffeineApp (the GUI application)

  • Basic Usage

    • caffeinate [options] [command]
    • When run without a command, keeps the system awake until interrupted (Ctrl+C)
    • When run with a command, keeps the system awake while the command executes

  • Common Options

    • -d - Prevent display from sleeping
    • -i - Prevent system from idle sleeping
    • -m - Prevent disk from idle sleeping
    • -s - Prevent system from sleeping (only if AC power adapter is connected)
    • -u - Simulate user activity and prevent display from sleeping
    • -t <seconds> - Timeout after specified number of seconds
    • Options can be combined (e.g., -di prevents both display and system sleep)

  • Examples

    • Keep system awake indefinitely

      • caffeinate - Run until interrupted (Ctrl+C)
      • caffeinate -t 3600 - Keep awake for 1 hour (3600 seconds)

    • Keep system awake for a specific duration

      • caffeinate -t 1800 - Stay awake for 30 minutes

    • Prevent display sleep while system can sleep

      • caffeinate -d - Keep display awake (useful when connected to external monitor)

    • Keep system awake during a command execution

      • caffeinate make build - Keep awake while building
      • caffeinate -d -i npm run test - Prevent display and system sleep during tests
      • caffeinate -u -t 7200 python long_script.py - Simulate user activity for 2 hours while script runs

    • Combined options for maximum wakefulness

      • caffeinate -di - Prevent both display and system idle sleep
      • caffeinate -dim - Prevent display, system, and disk idle sleep

  • Common Use Cases

    • Preventing sleep during long-running builds or tests
    • Keeping system awake during large downloads
    • Maintaining wake state during automated scripts
    • Preventing sleep during presentations or demos
    • Running overnight processes or backups

  • Comparison with GUI Alternatives

    • More scriptable and automatable than CaffeineApp
    • Can be integrated into build scripts and automation
    • No installation required (built into macOS)
    • Better suited for command-line workflows

  • Related Tools

    • CaffeineApp - GUI application with menu bar icon
    • pmset - macOS power management command-line tool for viewing/setting sleep settings

  • References

    • Apple Developer Documentation
    • View manual page: man caffeinate