By default, hidden files are, well, hidden in Finder on Mac OS X, and there is no method to enable viewing hidden files within the Preferences menu for Finder. But, there is a Terminal command you can use to enable viewing hidden files in Finder.
In Terminal, type this command:
defaults write com.apple.finder AppleShowAllFiles -boolean true
After you issue the above command you need to restart Finder. You can do this by issuing this command in Terminal:
..or alternatively, you can restart Finder by holding the Option (“Alt”) key while you right-click (two-finger-tap on touchpad) the Finder icon in the Dock and then choosing Relaunch.
Now you should be able to see hidden files in Finder.
If you later decide you want to disable viewing hidden files, change “true” to “false” in the command:
defaults write com.apple.finder AppleShowAllFiles -boolean false
How to show total combined file size of multiple files in Finder.
1. Highlight the files in Finder.
2. Press Option + Command + I to open the Multiple Item Info window.