Something

on *:JOIN:#: {
  .msg $chan %greet [ $+ [ $nick ] ]
  else { notice $nick To set a greet type !setgreet Greet here }
  on *:TEXT:!setgreet:#: {
    set $2- %greet [ $+ [ $nick ] ]
    .notice $nick you have set your greet to $2-
  }
}