Yesterday, we covered some basic Mac keyboard shortcuts. Today, we’ll check out some more useful options.

Option-Command-Esc Force Quit: Choose an app to force quit. Or press Command-Shift-Option-Esc and hold for 3 seconds to force just the front app to quit.
Command–Space bar Spotlight: Show or hide the Spotlight search field. To perform a Spotlight search from a Finder window, press Command–Option–Space bar. If you use multiple input sources to type in different languages, these shortcuts change input sources instead of showing Spotlight.
Space bar Quick Look: Use Quick Look to preview the selected item.
Command-Tab Switch apps: Switch to the next most recently used app among your open apps.
Shift-Command-Tilde (~) Switch windows: Switch to the next most recently used window of the front app.
Shift-Command-3 Screenshot: Take a screenshot of the entire screen.
Command-Comma (,) Preferences: Open preferences for the front app.

Log Out & Shutdown Options

              Shortcut Description
Power button Press to turn on your Mac or wake your Mac from sleep.Press and hold for 1.5 seconds while your Mac is awake to display a dialog asking if you want to sleep, restart, or shut down. If you don’t want to wait 1.5 seconds, press Control–Power button or Control–Media Eject  .*Press and hold for 5 seconds to force your Mac to turn off.
Control–Command–Power button Force your Mac to restart.*
Control–Shift–Power button or
Control–Shift–Media Eject 
Put your displays to sleep.*
Control–Command–Media Eject  Quit all apps, then restart your Mac. If any open documents have unsaved changes, you’ll be asked whether you want to save them.*
Control–Option–Command–Power button or
Control–Option–Command–Media Eject 
Quit all apps, then shut down your Mac. If any open documents have unsaved changes, you’ll be asked whether you want to save them.*
Shift-Command-Q Log out of your macOS user account. You’ll be asked to confirm.
Option-Shift-Command-Q Log out of your macOS user account immediately, without being asked to confirm.

~ Cynthia