Something

on *:TEXT:!setgreet*:#: { 
  set %greet [ $+ [ $nick ] ] $2- 
  notice $nick Your greet message has been set to: $2- 
} 

on *:TEXT:!delgreet*:#: { 
  unset %greet [ $+ [ $nick ] ] 
  notice $nick Your greet has been deleted 
} 

on *:JOIN:#: { 
  if (%greet [ $+ [ $nick ] ]) msg $chan [ $+ 7 $nick  $+ ]: %greet [ $+ [ $nick ] ] 
  else notice $nick You dont have a greet type !setgreet -greet- to set one 
}