my $cmd = <<EOF;
/usr/bin/ssh -t -i \$HOME/.ssh/LeadRNCkey -l usr machineC '/usr/bin/ssh -t -l usr machineD uname -a\\; mkdir \\\$HOME/.ssh\\; chmod go-w \\\$HOME\\; chmod go-w \\\$HOME/.ssh\\; echo \\"$public_key\\\n\\" \\>\\>\\\$HOME/.ssh/authorized_keys'
EOF