To display hidden files & folders
1. Open Terminal (from /Applications/Utilities)
2. Issue command
defaults write com.apple.finder AppleShowAllFiles -bool true
3. Kill the Finder to take effect by issuing the command
killall Finder
To hide them again, do as following
1. Open Terminal
2. Issue command
defaults write com.apple.finder AppleShowAllFiles –bool false
3. Kill the Finder to take effect by issuing the command
killall Finder