Mac OS X : show (hidden) .files in the finder.

Finder options:

1.  CMD + Shift + .

Terminal options + restart finder:

1. Open Terminal found in Finder > Applications > Utilities.
2. In Terminal, paste the following:
     defaults write com.apple.finder AppleShowAllFiles YES.
3. Press return.
4. Hold the 'Option/alt' key, then right click on the Finder icon in the dock and click Relaunch.

from :

https://ianlunn.co.uk/articles/quickly-showhide-hidden-files-mac-os-x-mavericks/