AppleShowAllFiles Command not working in Mavericks OS X 10.9
It worked for me in 10.9. You should be using -bool TRUE (not just TRUE), although it worked for me either way. Also, are you running it as two commands (killall Finder is a second command)? The only other thing I can think of is that cfprefsd might have the old setting (or lack therof) cached, so you may have to shut it down it first. If I understand the setup right, that shouldn't be necessary, but just in case:

killall cfprefsd
defaults write com.apple.finder AppleShowAllFiles -bool TRUE
killall Finder