use strict;
use warnings;

my $file = shift @ARGV;

open (my $fh1, $file) or die "Can't open file \"$file\", $!";

my @txt = <$fh1>;

close $fh1;

my $newtext = '"seq_name" "sequence.V6.0"';

my $i;


for ($i=0; $i <= $#txt; $i++) {
  last if $txt[$i]=~ m/"StrCatDone" "1"/;
  #print $txt[$i];
}

$txt[++$i]="$newtext\n";

open (my $fh2,">$file") or die "Can't open file \"$file\", $!";
print $fh2 @txt;