Questions[nix](server)

I am trying to create a .nix file that installs nvm

First I tried to add inside configuration.nix :

system.activationScripts = {

  dotfiles = pkgs.lib.stringAfters [ "users" ]
    ''
    curl NVM_URL | bash
    ''
  }
}

But it complained bash and curl are not defined....

So I tried to create a small .nix package,

{ stdenv, fileurl };
stdenv.mkDerivation {
   name="nvm-0.33.0"
   builder = ./install.sh;
   fileurl{
      url: NVM_GIT_MASTER.zip;
   };
}

But then it complain `cannot auto-call a function that has an argument without a default valu {'stdenv'}

After running nix-build --dry-run ./text,nix

What's going on? I am reading nix pages, and banging my head on the wall.

Will the other process be able to finish reading the old file even though it's been replaced?

This is a bit of an embarrassing question, but I have to admit that this late in my career I still have questions about the mv command.

I frequently have this problem: I need to move all files recursively up one level. Let's say I have folder foo, and a folder bar inside it. Bar has a mess of files and folders, including dot files and folders. How do I move everything in bar to the foo level?

If foo is empty, I simply move bar one level above, delete foo and rename bar into foo. Part of the problem is that I can't figure out what mv's wildcard for "everything including dots" is. A part of this question is this - is there an in-depth discussion of the wildcards that cp and mv commands use somewhere (googling this only brings very basic tutorials).

What happens to a TCP session when the IP of a client changes?

I did a simple test of having netcat listen on a port, and connecting to that port from a client machine. I then changed the IP of the client while that nc session was open and sent some data, no data was received by server after changing the IP.

1. I know they are different layers, but does TCP use IPs for part of how it distinguishes sessions?
2. Does my example not work because of how the application handles it, or is this not working because of something happening at TCP/IP/Ethernet layers?
3. Does this depend on the OS implementation? ( I am most interested in Linux at the moment)

I've been trying to get Java working on my FreeBSD 7.1 server. I just want the runtime, since the JDK drags all kinds of unnecessary dependencies with it, and I just need it to run a jar file periodically. I've installed the FreeBSD-supported diablo-jre, but whenever I try to run it, I get a:

/usr/local/diablo-jre1.6.0/bin/java: 2: Syntax error: "(" unexpected

So what to do?