Finder and system shortcuts :
* Command-D : Duplicate the selected files.
* Command-E : Eject the selected disk or volume.
* Command-F : Start a Spotlight search in the Finder window.
* Command-I : Show the Get Info window for a selected file.
* Command-R : (1) When an alias is selected in the Finder: show the original file for the selected alias. (2) In some apps, such as Calendar or Safari, refresh or reload the page. (3) In Software Update, check for software updates again.
* Shift-Command-C : Open the Computer window.
* Shift-Command-D : Open the desktop folder.
* Shift-Command-F : Open the Recents window, showing all of the files you viewed or changed recently.
* Shift-Command-G : Open a Go to Folder window.
* Shift-Command-H : Open the Home folder of the current macOS user account.
* Shift-Command-I : Open iCloud Drive.
* Shift-Command-K : Open the Network window.
* Option-Command-L : Open the Downloads folder.
* Shift-Command-N : Create a new folder.
* Shift-Command-O : Open the Documents folder.
* Shift-Command-P : Show or hide the Preview pane in Finder windows.
* Shift-Command-R : Open the AirDrop window.
* Shift-Command-T : Show or hide the tab bar in Finder windows.
* Control-Shift-Command-T : Add selected Finder item to the Dock (OS X Mavericks or later)
* Shift-Command-U : Open the Utilities folder.
* Option-Command-D : Show or hide the Dock.
* Control-Command-T : Add the selected item to the sidebar (OS X Mavericks or later).
* Option-Command-P : Hide or show the path bar in Finder windows.
* Option-Command-S : Hide or show the Sidebar in Finder windows.
* Command–Slash (/) : Hide or show the status bar in Finder windows.
* Command-J : Show View Options.
* Command-K : Open the Connect to Server window.
* Control-Command-A : Make an alias of the selected item.
* Command-N : Open a new Finder window.
* Option-Command-N : Create a new Smart Folder.
* Command-T : Show or hide the tab bar when a single tab is open in the current Finder window.
* Option-Command-T : Show or hide the toolbar when a single tab is open in the current Finder window.
* Option-Command-V : Move the files in the Clipboard from their original location to the current location.
* Command-Y : Use Quick Look to preview the selected files.
* Option-Command-Y : View a Quick Look slideshow of the selected files.
* Command-1 : View the items in the Finder window as icons.
* Command-2 : View the items in a Finder window as a list.
* Command-3 : View the items in a Finder window in columns.
* Command-4 : View the items in a Finder window in a gallery.
* Command–Left Bracket ([) : Go to the previous folder.
* Command–Right Bracket (]) : Go to the next folder.
* Command–Up Arrow : Open the folder that contains the current folder.
* Command–Control–Up Arrow : Open the folder that contains the current folder in a new window.