Problem persistently defining aliases in terminal
The alias command requires you to have no spaces around the = and also you should use " or ' to enclose the string not the curly quote ‘ you have. That quote often appears in pdfs and books when the editing program tries to make things look nice.

so the command should be 

alias showFiles="defaults write com.apple.finder AppleShowAllFiles TRUE; killall Finder"
alias hideFiles="defaults write com.apple.finder AppleShowAllFiles FALSE; killall Finder"


I can't find a reference for these but they are just things I have learnt :(