Basic tools are available, like 'ls' and 'grep'.
Getting anything a little less popular requires what I would term "jumping through hoops," as is the case with many Python dependencies I've encountered. It's especially horrible if the thing needs to be compiled. For a platform where the hardware always conforms to one of a set of fixed profiles, it's bizarre that there isn't a binary package manager for these things.
There are three!
* Fink
* Macports
* Homebrew
There are countless articles on the internet on which one is better than the other. The summary is that it depends on how closely you want the environment to look like Linux.
I've been using OSX for 3 years now, and I still ssh to a linux box to do date calculations with date
$ date -d "next sun" $ date -d "+3 years +2 months +3 hours -15 min"
All commands have been installed with the prefix 'g'.
% gdate -d "next sun"
Sun Dec 9 00:00:00 CST 2012
Hope this makes your day.