Otherwise, how?

he means something to the effect of:

alias face {
  return $replace($1, eyes, ಠ_ಠ ,jsmile, ( ﾟヮﾟ), teehee, ( ¬‿¬), etc,)
}

which is useful in case you want to be able to construct lines by using, for example, $face((eyes)_/ jsmile) = (ಠಠ)/ ( ﾟヮﾟ) ... y'know, creating full pictures with combinations of faces and other characters :P

otherwise, the method has a rather obvious shortcoming in that it doesn't validate $1. $1 could equal 'poop' and the alias would just return it. or it could be 'teeheepoop' and the alias would return '( ¬‿¬)poop'. sometimes we can get away with this; other times it requires extra code and becomes slightly more cumbersome to manage.

i've never been a fan of this kind of work since it's basically just data without any real code but then again i know some people come here to see ascii art and such ;)