$ssh->error and die "Couldn't establish SSH connection: " . $ssh->error;
$ssh->system('!bash') or die "remote command failed: " . $ssh->error;

# remote end will look like this after !bash
# bp>!bash
# [kburns@ssl01-d:Active] ~ # 

print "will never print this line\n";

$ssh->system('pwd') or die "remote command failed: " . $ssh->error;