To force Finder to display hidden files and folders via Terminal:
Open Terminal
For OS X 10.9 Mavericks, run this command (lower-case finder):
defaults write com.apple.finder AppleShowAllFiles TRUE
For OS X 10.8 Mountain Lion, 10.7, or 10.6, run this command (upper-case Finder):
defaults write com.apple.Finder AppleShowAllFiles true
notice the setting for true
Then run this command: killall Finder
Then exit Terminal
To revert back to Finder’s default setting (hide hidden files and folders),
run the opposite command but with the false setting.
Then run killall Finder and exit Terminal.