#! /usr/bin/perl

use Time::Local;

foreach $file ( @ARGV ){
   @fields = stat $file;
   
   @times = gmtime( $fields[9] );
   $times[4]++;
   $mon = "";
   $day = "";
   if( $file =~ /(sst)-(\d{2})(\d{2}).gif/ ){
      $prefix = $1;
      $mon = $2;
      $day = $3;
      }
   elsif( $file =~ /(sst_anom)-(\d{2})(\d{2}).gif/ ){
      $prefix = $1;
      $mon = $2;
      $day = $3;
      }
   if( $day ){
      $fsecs = timegm( 0, $times[1], $times[2], $day, $mon-1, 98 );
      @ftimes = gmtime( $fsecs );
      if( $ftimes[6] != 1 ){
         $fsecs = timegm( 0, $times[1], $times[2], $day, $mon-1, 99 );
         @ftimes = gmtime( $fsecs );
         }
      $fstr = scalar gmtime( $fsecs );
      }
   print "File: $file - $times[5] $times[4] $times[3] - $times[6] - $mon $day - $fstr\n";
   if( $day && $ftimes[6] == 1 ){
      $nfile = sprintf( "%s-%2.2d%s%s.gif", $prefix, $ftimes[5]%100, $mon, $day );
      print "exist\n" if( -e $nfile );
      print "Rename $file to $nfile\n";
      rename $file, $nfile;
      }
   }