It would have been nice if you'd specified exactly what you wanted, plus the example. But guessing at the format (untested): 
#!/your/perl/here
use strict;
use warnings;
my $sequence;

while (my $line = <>)
{
  # Sequence keyword
  if ($line =~ /^Sequence:\s+(contig\d+)/)
  {
    $sequence = $1;  # save the sequence
    next;
  }

  # Parameter keyword
  next if ($line =~ /^Parameters:\s+(.*)$/);

  # print any other non-blank lines
  if ($line != /^\s*$/)
  {
    print "$sequence $line";
    next;
  }
}

[download]
I don't know what your spec is for line breaks, or whether blank lines have meaning, or what to do for lines that don't begin with Parameter or Sequence keywords.

Please use <code> tags to show code and output, otherwise we have to check the page source to see the actual format. (And I still might have got the input format wrong.)

Update: Corrected Parameters: error as pointed out by Ovid. The Parameters: line is just skipped.

Update 2: Adding missing semicolon to Parameter line.

-QM
--
Quantum Mechanics: The dreams stuff is made of

In reply to Re: Perl Parser, need help by QM
in thread Perl Parser, need help by joomanji

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