Install chruby and ruby-build onto Ubuntu

_setup_chruby.sh

#!/bin/bash
# You can make some decisions in this file by (un)commenting parts, look through it first!
# Install:
#   aptitude install -y curl \
#     && curl -O https://gist.githubusercontent.com/2called-chaos/e06bf6322525d37a5bf7/raw/_setup_chruby.sh \
#     && chmod u+x _setup_chruby.sh
#
#   ./_setup_chruby.sh
#
# For Debian/Ubuntu you might also want to install these before building ruby:
#   aptitude install wget git build-essential autoconf bison libssl-dev libyaml-dev libreadline6 libreadline6-dev zlib1g zlib1g-dev
#
# For CentOS/RedHat you might also want to install these before building ruby:
#   yum install wget git gcc gcc-c++ kernel-devel make autoconf bison openssl-devel libyaml-devel readline readline-devel zlib zlib-devel

### START CONFIG

# The version of chruby to install (check for more recent version)
VERSION="0.3.9"

# where to install ruby-build
RUBY_BUILD_PATH="/opt/ruby-build"

# where to link the ruby-build executable to? (omit bin/ruby-build)
RUBY_BUILD_PREFIX="/usr/local"

### END CONFIG

# requirements
python -mplatform | grep Ubuntu && sudo aptitude install git wget || sudo yum install git wget

# stop script of command fails
set -e

# get & install
cd /usr/local/src
wget -O chruby-$VERSION.tar.gz https://github.com/postmodern/chruby/archive/v$VERSION.tar.gz
tar -xzf chruby-$VERSION.tar.gz && rm chruby-$VERSION.tar.gz
cd chruby-$VERSION/
sudo make install

# load in every bash session
cat > /etc/profile.d/chruby.sh <<EOF
[ -n "\$BASH_VERSION" ] || [ -n "\$ZSH_VERSION" ] || return

source /usr/local/share/chruby/chruby.sh
EOF

# prepare ruby folder
mkdir -p /opt/rubies/

# get ruby-build
git clone https://github.com/sstephenson/ruby-build.git $RUBY_BUILD_PATH
cd $RUBY_BUILD_PATH
./install.sh PREFIX=$RUBY_BUILD_PREFIX

echo "Done, you can now install rubies with \`ruby-build 2.whatever /opt/rubies/2.whatever'"