What is the most OSX or Darwin-like command-line experience available (without buying an expensive Mac or hauling my production machines home)? I want to emulate the command-line experience from OSX with a small netbook and practice my skills with the comfort of this small machine.

Surely Apple offers actual Darwin Links for developers or sysadmins...  their url is even "OpenSource.Apple.com," but so far the images I've found in web-archives seem even older; see for example this post or this unix &amp; linix post.  

I thought FreeBSD would provide this, and I'm loving using FreeBSD, but OSX has incorporated so much more into the systems that I feel like it is not accurate training or the answer to my question.

It is possible to get an .iso of so-called Pure Darwin (The successor to Open Darwin), but it seems like it focuses on VMware images and getting people into a GUI (which is cool, but not my goal here), plus it is naturally a bit out of date.  Thanks.
Use ssh on the netbook to log into a remote Mac and learn the commands that way.