[18:45][nick:~/monks]$ cat test.dat 
foo
bar
baz
quux

[18:45][nick:~/monks]$ cat 1135741.pl 
#! perl -w
use strict;
use feature qw/ say /;

use Path::Tiny qw/ path /;

my $file = 'test.dat';
my @lines = path( $file )->lines( { chomp => 1 } );

#my @append = (); # empty array
path( $file )->append( '', { truncate => 1 } );

say "Done.";

__END__

[18:45][nick:~/monks]$ perl !$
perl 1135741.pl
Done.
[18:45][nick:~/monks]$ cat test.dat 
foo
bar
baz
quux

HASH(0x7fa310898690)