Hi, I would use something like this:

#!/usr/bin/perl

use strict;
use warnings;

open(my $fh, '<', "test") or die("Could not open file: $!\n");
my @lines;

while (<$fh>) {
    next if $_ eq "\n";
    s/\n/ /;
    push @lines, $_;
}

my $long_line = join('', @lines);
print $long_line, "\n";
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