ar -  Tells the system that you're annoyed

dd -  Du Doof ?

rm *     -  Read all mail
rm -R *  -  Read all mail (recursively, even older ones)
rn       -  Read news
ranlib * -  your knowledge is running short

SMTP = Simple McDonalds Transfer Protocol
RFC  = Royal Fritten ChickenMCNuggest
FTP  = Frass Transfer Protocol
UDP  = User Doof Detection