Prerequisites

You need a working installation of Ruby (at least version 1.8.2) and of pdftex.

Download

First of all, you need to get a working copy of Tioga, the wonderful plotting library that Ctioga is based on. You can get it here . You should always get the latest version, as the author of Ctioga is also actively taking place in the developpement of Tioga, and ctioga is often using recent features of Tioga.

Then, download ctioga itself here. I will assume that you downloaded ctioga version 1.0 and Tioga version 1.2.0.

Installation

First, unpack both the archives you did download. A mere 
tar xvzf file.tar.gz
on both files should do it.

There are two ways to do the actual installation.

With administrator privileges

If you have administrator privileges on your computer, you can try the following:

cd tioga-1.2.0
sudo ./QUICK_INSTALL
cd ..
cd ctioga-1.0
sudo ./INSTALL

where you need to replace the dots by the actual name of the directory extracted.

Unprivileged user

Without privileges, you might want to try this 
cd tioga-1.2.0
./HOME_INSTALL
cd ..
cd ctioga-1.0
./HOME_INSTALL

However, in this case, as the installation scripts should remind you, you should set the RUBYLIB environment variable appropriately. For instance, if your login shell is bash (the standard on most of Linux distributions), add the following lines to the file .bashrc found on your home directory:

RUBYLIB=$HOME/lib/ruby
export RUBYLIB

Install somewhere else ?

Sometimes, it can be very useful to install somewhere else. A simple example here shows how to install to an arbitrary directory, with a lib/ruby and bin/ substructure:

ruby extconf2.rb --home
make install HOME=/home/vincent/bidule

This will install ctioga in the /home/vincent/bidule/lib/ruby/ and /home/vincent/bidule/bin directories. If you need more fine-tuning, I suggest you have a look at the Makefile produced; it should be very easy to see which variable controls which installation.

Rubygems

Since versions 1.4 of Tioga and 1.2 of ctioga, it is now possible to install the programs using Rubygems. Doing the following should just run perfectly fine:

gem install ctioga

Debian users…

Debian packages are available. Just try

apt-get install ctioga