To show hidden files in Finder windows (e.g. .files and the Library folder)
launch the terminal and enter: defaults write com.apple.Finder AppleShowAllFiles TRUE
hold option, click on Finder icon in dock
from popup menu, choose relaunch
to hide hidden files
launch the terminal and enter: defaults write com.apple.Finder AppleShowAllFiles FALSE
hold option, click on Finder icon in dock
from popup menu, choose relaunch