#! /usr/bin/ksh 
  typeset -Z2 mon
  mon=12
  year=05
  while ((mon<13))
  do 
    mkdir /nilu_wrk6/OPER_fields_GFS/20$year/$mon
    mv AV${year}${mon}* /nilu_wrk6/OPER_fields_GFS/20$year/$mon 
    ((mon=mon+1))
  done