A hidden file is a file which is not shown to the user in general circumstances. Hidden files may still be shown to the user depending on the user's preferences or the method they are using to view files.
Files in OS X may be hidden by prepending the file name with a
., or by setting the 'hidden' flag on a file or folder using
chflags hidden /path/to/file.
Hidden files may be viewed with Finder by setting the AppleShowAllFiles preference with
defaults write com.apple.finder AppleShowAllFiles YES, or with ls by using the