Slurping the file into an array would be more efficient.

hints below 

...
open FILE, "<$ARGV[0]";
@data_records=<FILE>;
for ($x=0;$x<@data_records;$x++){
   for ($index=$x; $index<($x+5);$index++){
      @record=split(/\s+/, $data_records[$index]);
      for($index=1;$index<@record;$index++){
         $max[$index]=$record[$index] if $max[$index]<$record[$index];
      }
   }
   print "$ARGV[0]-",$ARGV[0]+5,"@max\n";
}

[download]
EDIT, Re-read now trying to answer the question actually posed

In reply to Re: creating and printing a sliding window by Utilitarian
in thread creating and printing a sliding window by Angharad

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