Here'a quick update for eveyone who offered help: First: THANKS!! You guys and gals are great. Your comments and thoughts proved most useful, and helped me think about my problem from a different viewpoint, which ultimately proved to solve my problem. A special thanks to 'beable' who told me about the Tie::File module, which for all intents and purposes saved my bacon. I will note, however, that Perl PPM was less than successful in installing this particular module (as well as a number of others, which leads me to believe that the problem is, perhaps, me... :) )...After much reasearch, however, I was able to install this handy module the archaic way. In anycase, this may not be the most efficient way of doing this, but it works, and that's all I needed. Here's the code that solved my problem: 
tie @array, 'Tie::File', "mdfl.txt";

foreach $line (@update) {  
  chomp $line;         
  @bob = split (/\t/, $line);  
    $dmpiid = $bob[0];
    $new = $bob[1];                
    $ln = "-1";
        {
    foreach $element (@array) {
      $ln ++;
             if (($element) =~ (/$dmpiid/)) {
             print "Match found at $ln\n";
         $slice = $array[$ln];
         @fred = split (/\t/, $slice);

           $dmpi = $fred[0];
           $benum = $fred[1];
           $os = $fred[2];
           $name = $fred[3];
           $lat = $fred[4];
           $long = $fred[5];
           $last = $fred[6];
           $curr = $fred[7]; 

           $last = $curr;
           $curr = $new;

$array[$ln] = "$dmpi\t$benum\t$os\t$name\t$lat\t$long\t$last\t$curr";
                next;
                }
            } 
             } 
}
untie @array;

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In reply to flat file databases by Travis M.

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