<INFIL> =~ /^cpu\s+(\d+)\s+(\d+)\s+(\d+).*/;
   @loads  = ($1, $2, $3);
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You're using $1 without testing whether the match succeeded. Either add "or die" to your matches (if not matching would be an exceptional condition), or put your use of $1 within the context of a conditional statement based on the match success.