That's a useful fix! Any chance for this to be merged?

Can someone provide steps how to reproduce this?

@domenkozar, here is an example configuration with a nixos-container running on the VirtualBox host:

{
  vbox =
    { deployment.targetEnv = "virtualbox";
      deployment.virtualbox.memorySize = 512;
      deployment.virtualbox.vcpu = 1;
      deployment.virtualbox.headless = true;
    };

  machine =
    { resources, ... }:
    { deployment.targetEnv = "container";
      deployment.container.host = resources.machines.vbox;
    };
}

The nixops ssh machine fails with the following error:

nc: invalid option -- 'c'
usage: nc [-46bCDdhjklnrStUuvZz] [-I length] [-i interval] [-O length]
  [-P proxy_username] [-p source_port] [-q seconds] [-s source]
  [-T toskeyword] [-V rtable] [-w timeout] [-X proxy_protocol]
  [-x proxy_address[:port]] [destination] [port]
machine> could not connect to ‘root@192.168.56.101~10.233.1.2’, retrying in 1 seconds...

@RostakaGmfun yes, that's the same issue I was facing. I am currently full of work, cannot follow up that well in this PR at the moment.

d7411ed Testing without -c on netcat bsd and gnu seemed to work.