su root -c "whoami"

##</code><code>##

my $ssh2 = Net::SSH::Any->new('192.168.XX.XXX, user => 'root', password => 'root');
print $ssh2->capture({stdin_data => "$sudo_passwd\n"},
                     'sudo', '-Sk',
                     '-U', $user,
                     '-p', '',
                     '--',
                     'whoami');