It tidies up nicely and does less searching if you modify the foreach loop: 
   foreach $searchstring (grep {!exists $guard{$_}} @array)
     {
     if (m/$searchstring/i)
       {
          push @stringsfound, $searchstring;
          $guard{$searchstring} = undef;
       }
      }

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Caution: Contents may have been coded under pressure.

In reply to Re^2: Match a string only once in a file by Roy Johnson
in thread Match a string only once in a file by newbie2perl

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