Command+X Cut: Remove the selected item and copy it to the Clipboard.

Command+C Copy the selected item to the Clipboard.

Command+V Paste the contents of the Clipboard into the current document or app. This also works for files in the Finder.

Command+Z Undo the previous command. You can then press

Command+Shift+Z to Redo, reversing the undo command. In some apps, you can undo and redo multiple commands.

Command+A Select All items.

Command+F Find: Open a Find window, or find items in a document.

Command+G Find Again: Find the next occurrence of the item previously found.

Command+H Hide the windows of the front app. To view the front app but hide all other apps,

Command+M Minimize the front window to the Dock. To minimize all windows of the front app,

Command+N New: Open a new document or window.

Command+O Open the selected item or open a dialog to select a file to open.

Command+P Print the current document.

Command+S Save the current document.

Command+W Close the front window.

To close all windows of the app, press Command+Option+W.

Command+Q Quit the app.

Option+Command+Esc Force Quit: Choose an app.

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.

Command-Comma (,) Preferences: Open preferences for the front app.

Take a screenshot of part of your screen

• Press Command-Shift-4. The pointer changes to a crosshair pointer.

• Move the crosshair pointer to where you want to start the screenshot.

• Drag to select an area. While dragging, you can hold the Shift key, Option key, or Space bar to change the way the selection moves.

The same steps also work if u want to screenshot menu's

The picture below was done by doing Command + Shift + 4

Screenshot the whole computer If u have a MAC Book and u go to Finder and type Chat in the finder it will bring all your text messages up on your computer.