Usage: SET INPUT_ALIASES [ON|OFF|TOGGLE]
  Turns ON or OFF the expanding of aliases in the inputline, 
  If you set INPUT_ALIASES ON and type: ECHO $S
  you will see your server name echoed to your window.  If it is
  OFF, you will see $S echoed to your window. INPUT_ALIASES now 
  has no effect on expansions in the .ircrc and loaded files.  To 
  Make a line expand when a file is loaded, use EVAL <command>.

  Note also, that when INPUT_ALIASES is ON, text within (..) and {..}
  are not expanded.  If you want them to be expanded then quote the 
  leading ( or {.  e.g.   \(  \{ 

  Additionally, You can return to full alias substitution
  within ${...} by enclosing the substitution text in
  [...]. Thus  if $0 == test, and $bear == black
          ${[$0]} expands to "test"
          ${[$bear]} expands to "black"
          ${bear} also expands to "black"
          ${ bear == [black] }  expands to "1",
          ${ [$0] == [test] } expands to "1"
          ${ [$0] == [black] } expands to "0"
          ${ [$0](this) } expands to the return value of $test(this)
  
Note:
  If you do turn on INPUT_ALIASES in the .ircrc then the argument
  expandos ($*, $0, $1, $3-4, etc) will expand to the command line 
  arguments passed to IRCII on startup.