A reasonable Ruby install script. Includes "essential" deps.

install_ruby.sh

# This build script will build Ruby 2.0.0-p247. You will need su to
# root or sudo as required.

# This build tested against Debian 7.0 64-bit arch, installed from net-inst image.

# These aren't specifically Ruby deps; more for building software in general
# (you probably already have them)
apt-get install -y build-essential autoconf

# These deps will support common libraries like yaml and give you the best irb experience.
apt-get install -y bison zlib1g-dev libssl-dev libreadline6-dev libncurses5-dev file libyaml-dev libxslt1-dev libxml2-dev openssl

# Create a directory for our source code
mkdir -p src && cd src

# Grab Ruby package and expand
# Debian netinst comes with wget out of the box; you can also use curl -O <url>
# if it's available
wget ftp://ftp.ruby-lang.org/pub/ruby/2.0/ruby-2.0.0-p247.tar.gz
tar xzf ruby-2.0.0-p247.tar.gz

# Pause here to check the MD5 sum of the downloaded package using the following command.
# The checksum should equal the value supplied by https://www.ruby-lang.org/en/downloads/
# Outputs 'Checksum is a go!' if passed. If you get silence, DO NOT proceed,
# and figure out why your download was compromised.

#   test $(md5sum ruby-2.0.0-p247.tar.gz | cut -d' ' -f1) = c351450a0bed670e0f5ca07da3458a5b && echo 'Checksum is a go!'

cd ruby-2.0.0-p247

# Build Ruby!
# Configure flags explanation:
#   prefix=/usr/local is probably default, but I specify to be sure
#   enabled-shared option builds libruby.so, which you may need later
#   docdir puts docs in a Debian standard location (you may want something different)
./configure --prefix=/usr/local --docdir=/usr/share/doc/ruby-2.0.0 --enable-shared && make
make install