my $fnpubcert = "/home/localusername/.ssh/id_rsa.pub";
open my $fhpubcert, '<', $fnpubcert or die "error opening $fnpubcert $!";
my $mypubcert = do { local $/; <$fhpubcert> };

##</code><code>##

my $cmd = "echo $mypubcert > /home/remoteusername/.ssh/authorized_keys";
my ($stdout,$stderr,$exit) = $ssh->cmd("$cmd");
if ($stdout || $stderr) { print "STDOUT: $stdout STDERROR: $stderr\n"; }
my $cmd = 'chown remoteusername.remoteusername /home/remoteusername/.ssh/authorized_keys; chmod 600 /home/remoteusername/.ssh/authorized_keys';
my ($stdout,$stderr,$exit) = $ssh->cmd("$cmd");
if ($stdout || $stderr) { print "STDOUT: $stdout STDERROR: $stderr\n"; }

##</code><code>##

my $cmd = "cat > /home/vmsys/.ssh/authorized_keys";
print $mypubcert | my ($stdout,$stderr,$exit) = $ssh->cmd("$cmd");