set dotVisible to do shell script "defaults read com.apple.Finder AppleShowAllFiles"
if dotVisible = "0" then
do shell script "defaults write com.apple.Finder AppleShowAllFiles 1"
else
do shell script "defaults write com.apple.Finder AppleShowAllFiles 0"
end if
tell application "Finder" to quit
delay 1
tell application "Finder" to activate