on *:TEXT:brb*:*: { 
  set %berightback $nick
  set %reasonforbrb $2-
  set %awaytime $ctime
  msg $chan 7 $nick 10is now: 7AWAY10 :: Reason:7 %reasonforbrb 10:: Left at:7 $asctime( $ctime )hh:nn:ss)
} 

on *:TEXT:back:*: { 
  if (%berightback == $nick) {
  msg $chan 7 %berightback 10is now: 7BACK10 :: Reason:7 %reasonforbrb 10:: Gone for:7 $duration($calc( $ctime - %awaytime )) } 
  unset %berightback
  unset %reasonforbrb
unset %awaytime }
}