my $cmd = "/usr/bin/ssh -t -i \$HOME/.ssh/privkey user\@machineC '/usr/bin/ssh -t -l user machineD \"mkdir \$HOME/.ssh;chmod go-w \$HOME && chmod go-w \$HOME/.ssh && ( echo $public_key ) >>\$HOME/.ssh/authorized_keys\"'";

##</code><code>##

#/usr/bin/ssh -t -i \$HOME/.ssh/privkey user\@machineC '/usr/bin/ssh -t -l user machineD mkdir \\\$HOME/.ssh;chmod go-w \\\$HOME && chmod go-w \\\$HOME/.ssh && ( echo $public_key ) >>\\\$HOME/.ssh/authorized_keys';

##</code><code>##

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