Did you know you can use keyboard shortcuts to navigate tabs in the Safari web browser of macOS Sierra? Well, you can.
Just hold down Command + Shift, then tap the Left and Right arrow keys move through through the browser tabs from left to right or right to left. Or you can hold down Command + Shift, then tap the Open or Close Bracket keys to move through the browser tabs from left to right or right to left.
You can find more shortcuts here (https://support.apple.com/kb/PH21483?locale=en_US).
(This how-to is based on my experiences and info on Apple’s support pages — where the images sometimes come from.)
