Instead of @required and @all and the foreach:

while (<FH>)
{
  print C $_ if /^abcde.*PARTNAME$/;
}
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Note that if either "abcde" or "PARTNAME" (or both) are variables, but don't change while reading this particular file, I would compile that regexp once:

my $re = qr/^$start.*$end$/;
while (<FH>)
{
  print C $_ if m/$re/;
}
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Another possible improvement may be to remove the .* and do two matches:

my $startre = qr/^$start/;
my $endre   = qr/$end$/;
while (<FH>)
{
  print C $_ if m/$startre/ and m/$endre/;
}
[download]

Also, please put your code into <code> and </code> tags - makes it much easier to read. Thanks.