In macOS Sierra Apple added a Finder keyboard shortcut that makes it possible to quickly show all the hidden files and folders. You just need to do the following:
- Open the Finder
- Go to your Macintosh HD folder (access this from Devices in the left column)
- Hold down Cmd + Shift + . (dot)
- All the hidden files will become visible
- Hold down Cmd + Shift + . (dot) a second time to hide the files again