To download and compile Eulora's 2.0 client:

1. Install the required system packages 
The exact list here will depend on the OS but the main parts are: autotools (required by Cal3d and CS), ftjam (or jam, required by CS), the "dev" packages (on distributions that have those separate, hence Ubuntu/Debian for sure) for any libs that are used by CS (this includes for sure the libs for compression (zlib), image formats (png, jpg), 2D fonts (libcairo) and x and widgets (x and wx)),  Nvidia CG toolkit (for reasonable graphics - things like water looking in the least like water for instance but otherwise the client will still run without this too).

For ftjam, there's a version known to work with Eulora's client at http://ossasepia.com/eulora2/ftjam-2.5.2.tar.gz (signature: http://ossasepia.com/eulora2/ftjam-2.5.2.tar.gz.sig).

NB: the install script REQUIRES gpg and wget to be able to check and download files, respectively.

Current known-to-work list:
Ubuntu 10:
autoconf, bison, build-essential, curl, doxygen, flex, ftjam, g++, lib3ds-dev, libasound-dev, libcairo-dev, libcairomm-1.0-dev, libcal3d-dev, libcppunit-dev, libfreetype6-dev, libgl1-mesa-dev, libgtk2.0-dev, libjpeg-dev, liblcms-dev, libmng-dev, libode-dev, libogg-dev, libopenal-dev, libpng12-dev, libspeex-dev, libtool, libvorbis-dev, libwxbase2.8-dev, libwxgtk2.8-dev, libx11-dev, libxaw7-dev, libxext-dev, libxrender-dev, libxxf86vm-dev, mesa-common-dev, nvidia-cg-toolkit, pkg-config, python-dev, subversion, swig, zlib1g-dev

Ubuntu 14.04:
autoconf bison build-essential curl doxygen flex ftjam g++ lib3ds-dev libasound-dev libcairo2-dev libcairomm-1.0-dev libcal3d12-dev libcppunit-dev libfreetype6-dev libgl1-mesa-dev libgtk2.0-dev libjpeg-dev liblcms1-dev libmng-dev libode-dev libogg-dev libopenal-dev libpng12-dev libspeex-dev libtool libvorbis-dev libx11-dev libxaw7-dev libxext-dev libxrender-dev libxxf86vm-dev mesa-common-dev nvidia-cg-toolkit pkg-config python-dev subversion swig zlib1g-dev

Debian 8 (Jessie):
autoconf bison build-essential curl doxygen flex ftjam g++ lib3ds-dev libasound2-dev libcairo2-dev libcairomm-1.0-dev libcal3d12-dev libcppunit-dev libfreetype6-dev libgl1-mesa-dev libgtk2.0-dev libjpeg-dev liblcms2-dev libmng-dev libode-dev libogg-dev libopenal-dev libpng12-dev libspeex-dev libtool libvorbis-dev libx11-dev libxaw7-dev libxext-dev libxrender-dev libxxf86vm-dev mesa-common-dev pkg-config python-dev subversion swig zlib1g-dev
NB: you'll have to install nvidia-cg-toolkit separately (from nvidia's site).

Xubuntu 24.04.1 LTS:
autoconf automake libtool zlib1g-dev libpng-dev libjpeg-dev libcairo2-dev libx11-dev libgl-dev nvidia-cg-toolkit

NB: you'll have to install ftjam separately, there's a signed copy at http://ossasepia.com/eulora2/ftjam-2.5.2.tar.gz (signature: http://ossasepia.com/eulora2/ftjam-2.5.2.tar.gz.sig )

2. Download the install_eulora.sh script in a dir of your choice, read it and if you are fine with its contents, make it executable and run it. For example:

wget -O install_eulora.sh http://ossasepia.com/eulora2/install_eulora.sh
chmod +x install_eulora.sh
./install_eulora.sh

That's it. It can take a while (~1 hour or more, depending on your connection and machine) for the work to finish. The script will output instructions on how to run the client and get into the game.

NB: if you are on Xubuntu 24.04.1 LTS or other similarly recent OS, you will likely need to uncomment some parts in the install_eulora.sh script for everything to work - read through it and change it as needed for your case.
NB: any changes required for the install_eulora.sh script are ALSO required for the update_eulora.sh script so make sure to make the changes in both.

Note that the install_eulora.sh script installs a working version of the client and you can fully connect and play the game with it but it won't be the latest client version so you might be missing some functionality. To update to the latest version of the client, see next step (the update_eulora.sh script).

3. Optional, only *after* a successful run of the install_eulora.sh script: download the update_eulora.sh script in the same dir as install_eulora.sh, read it and if you are fine with its contents, make it executable and run it. For example:

wget -O update_eulora.sh http://ossasepia.com/eulora2/update_eulora.sh
chmod +x update_eulora.sh
./update_eulora.sh

NB 1: the update_eulora.sh script will work only *after* a successful run of the install_eulora.sh script, NOT before that. ANY changes made to install_eulora.sh should be made to update_eulora.sh as well (or otherwise the update will fail).

NB 2: after a successful run of the install_eulora.sh script, do NOT re-run it, as it will overwrite the existing install. To update the client, always run the update_eulora.sh instead.