Didn't actually get what do you want, but here's the code that assigns new value to line 6:

use strict;
use warnings;

my $fileName = shift;

#open the file and copy to an array
open my $fh, "<", $fileName or die "Cannot Open File: $!";
my @aFile = <$fh>;
close $fh;

# use $aFile[-1] for the last line, and $aFile[5] for the 6th line
$aFile[5] = qq(<xxxx.xxx.xxx.xxx, "xxx", xx_$fileName, xxx="">);
[download]