use warnings;
use strict;
use Data::Dump;

open my $fh, '<', 'test.txt' or die $!;
my @lines = do { local $/=''; <$fh> };
chomp @lines;
close $fh;

dd @lines;

__END__

("line1\nline2\n", "line4\n", "line7\nline8\n", "line9\n")

##</code><code>##

open my $fh, '<', 'test.txt' or die $!;
while (my $line = <$fh>) {
	print $line if length $line && $line ne $/;
	# - OR -
	push @newlines, $line if length $line && $line ne $/;
	# - OR -
	chomp($line);
	next unless length $line;
	print $line, "\n";
	# etc.
}
close $fh;