use warnings;
use strict;
use Perl::Critic;
use Net::SSH::Perl;
use Net::SSH::Perl::Key::RSA;
use Class::ErrorHandler;

my $server="400.800.400.800"; #not a real IP address
my $port="22";
my $username="snoopy";
#my $command="df -h"; #this worked
#my $command="ls"; #this worked
#my $command="sh status.sh"; #Received error Use of uninitialized value $stdout in string at ssh.pl 
#my $command="/usr/bin/sh status.sh"; #Received error Use of uninitialized value $stdout in string at ssh.pl 
#my $command="qstat"; #Received error Use of uninitialized value $stdout in string at ssh.pl line 
my $command="pwd"; #this worked

my $ssh = Net::SSH::Perl->new("$server", protocol=> 2, port=>"$port", identity_files=>["/location/of/my/identity/files/file"]);

$ssh->login($username);
my($stdout, $stderr, $exit) = $ssh->cmd("$command");

print "$stdout";