Hidden Features

Several features and options which seem to have been removed in later versions of macOS but are in fact just hidden. Some of them for instance can be used via Terminal commands instead, others by just pressing the ⌥ Alt key (the one called "option" key in the early days) while performing certain actions such as expanding a menu or a popup button.

Hidden features/options

... to be revealed by pressing/holding certain keys or key combinations:

All Applications

Making screenshots of a window

…by using the well-known key combination ⌘ Cmd ⇧ Shift 4 for grabbing the whole screen, followed by pressing the Space bar. The cursor then changes into a camera icon and lets you select a window to be snapped by simply tapping/clicking on it.

Finder

Enter the user's "Library" folder

…by pressing the ⌥ Alt key while opening the Finder menu "Go", which will reveal the respective entry. You can altenatively follow the next hint for achieving pretty much the same thing by making the folder visible 👇

Reveal hidden files and folders

…in Finder windows and Open/Save file dialogs by pressing the combination ⌘ Cmd ⇧ Shift .
Repeat this to hide them again. The setting is only temporary in file dialogs (i.e. until the rspective dialog is being closed) and persistent until the next login (until the Finder is being relaunched to be precise) in Finder windows. The next hint will tell you how to do that 👇 (relaunching the Finder).

Relaunch the finder

…without a logout or reboot by pressing and holding the ⌥ Alt key before opening the contextual menu of the Finder's Dock Icon. This will reveal the respective menu entry.

Minimize all windows of an app

…by pressing and holding the ⌥ Alt key while minimizing one of them using its green traffic light button in the top left corner.

Preview

Export images to other file formats

…by pressing and holding the ⌥ Alt key before expanding the "Format" popup button on the "Save file" dialog. This will reveal additional image formats to save an image in, such as ICNS or Photoshop.

Easter Eggs

Get a full LOTR timeline

…by running the Terminal command cat /usr/share/calendar/calendar.lotr (tested on macOS Monterey)

Get historical events

…for (almost) every calendar day by running the Terminal command cat /usr/share/calendar/calendar.history (tested on macOS Monterey). Get those for a specific day by filtering its output: cat /usr/share/calendar/calendar.history | grep 01/01

Get a cookie recipe

…by running this Terminal command on macOS Mojave: open /usr/share/emacs/22.1/etc/COOKIES (seems to be not around any longer on more recent macOS versions such as macOS Monterey or Ventura)

See also

Apple Applications

• Safari Web Browser
• the macOS Dock

Third Party Applications

• Firefox Web Browser

External Resources

• Mac Keyboard Shortcuts
• Startup Key Combinations