For Ubuntu... I would recommend the package manager. Not sure where it is, but somewhere on the menu. Most linuxes these days use package-based software distribution. What that means is that if you want some program, or some library (think .dll files), instead of going to the site of whoever programmed it, you use a central repository. Developers submit their packages to the repository, and they become available to everyone from a single source. This method has it's problem, but in general it works out pretty nicely.
Now, apt or aptitude are programs that allow you to download and install these packages. So what you're going to need to do is get ncurses, then get the compilers, then get the source code, and then compile. ncurses is a library (just a piece of independent code that programmers can reuse) that allows you to draw characters on-screen. Most roguelikes use ncurses or a similar library to show stuff on screen. libncurses5 is the library itself that you need to run stuff that uses ncurses, whereas libncurses5-dev is the version that you need to compile code that uses ncurses (taking source code and making it into an executable).
git is simply a program that allows you to share your source-code with people. It allows multiple developers to work on the same piece of software independently without screwing up everything and overwriting each other's stuff.
First things first: you need to get all the packages for the software you're going to need.
To get the source code, you need "git". The ubuntu package name is "git" (search on packages.ubuntu.com).
To get all compiler related stuff, you want a package called "build-essential". It has all you'll need! Easy, 'innit?
To get the ncurses stuff for compilation, you need libncurses5-dev (apparently libncurses5 is already installed)
How do you get this? You use aptitude, but you need administrator privileges, so you do "sudo" (super-user do). All of this is done in a terminal. First you update the package information from your repository:
"sudo aptitude update"
Then, you tell it to install the packages you need:
"sudo aptitude install git build-essential libncurses5-dev", this is what you want to run. It will ask you for your password. Just put that in and press enter. It should install.
Once you've done that, the other guides on this thread should work. Run git clone with the git repository, then run "make clean" and then "make". To run the game, just type "./cataclysm". If the screen is all black, try increasing the size of the terminal window.
I hope this helps you guys a bit. I know linux is complicated - but there's no reason to get this pissed off about it. If you only run linux, you also don't have access to most games... people insist on using directX and windows-only technologies, essentially making games almost impossible to run on Mac or Linux. Ain't fun to be on the other side, I know. Besides, cross-platform programming isn't as easy as you guys seem to think it is, as evidenced by problems in the windows version.