Read up on split

  open (IF, "<$thefile");
      $rawstring = (<IF>);
  close (IF);
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Do you want to read just the first line of your file?
To split $rawstring and place into an array is as simple as @array = split(/;/, $rawstring);
You don't need to escape the semi-colon and the < in the open is optional. Default case for open is read.