Compile ruby 1.9.2 on Ubuntu

assumes you have build-essential package installed

wget http://ftp.ruby-lang.org/pub/ruby/1.9/ruby-1.9.2-p0.tar.bz2
tar -xjvf ruby-1.9.2-p0.tar.bz2
cd ruby-1.9.2-p0
./configure --enable-shared --program-suffix=1.9.2
make
make check # optional
sudo checkinstall make install
# [follow the defaults until here:
# NOTE that you want the extra files inside your directory.
# those extra files contain things like the openssl libraries!!

    Some of the files created by the installation are inside the build
    directory: /home/jtprince/src/ruby-1.9.2-p0

    You probably don't want them to be included in the package,
    especially if they are inside your home directory.
    Do you want me to list them?  [n]: n
    Should I exclude them from the package? (Saying yes is a good idea)  [y]: n

# At this point, you can install the package on machines of the same
# architecture with "sudo dpkg -i ruby-1.9.2_p0-1_amd64.deb" [depending on your arch]

sudo rm /usr/bin/ruby
sudo ln -s /usr/local/bin/ruby1.9.2 /usr/bin/ruby

Okay, now you need to get rubygems working properly. Remember, rubygems comes with ruby 1.9.X, so you don't need to download it separately.

At this point, we have to ensure our soft links point where we want and to tell gems to point to ruby 1.9.2

sudo cp /usr/bin/gem1.9.{1,2}
# then edit /usr/bin/gem1.9.2
# change #!/usr/bin/ruby1.9.1 ==> #!/usr/local/bin/ruby1.9.2

# now set up the soft link so that "gem" calls our gem1.9.2
sudo rm /etc/alternatives/gem
sudo ln -s /usr/bin/gem1.9.2 /etc/alternatives/gem

Maybe it is unnecessary, but I moved my local gem folder so that all my gems are compiled from scratch again to ensure they have been built against 1.9.2. how to set up a local gem environment

mv ~/.gem/ruby/{,not_using_}1.9.1
mkdir ~/.gem/ruby/1.9.2