Ruby version management on Debian

deploy.rb

require "bundler/capistrano" # runs bundle:install on remote for us

# give cap the correct path to our custom installed rubies
default_environment['PATH'] = "/usr/local/ruby/bin:/usr/bin:/bin"


# ... rest of normal cap config

install.sh

#!/bin/sh

# This is not meant to be used as an actual script.
# Just the series of commands I run from the command line to set things up.

# git and the usual build dependencies needed to get a fully operational ruby
apt-get update
apt-get install git build-essential libssl-dev libreadline5-dev libxml2 libxml2-dev libxslt1-dev
 readline-common openssl zlib1g zlib1g-dev make gcc autoconf libtool file curl libcurl4-openssl-dev

# clone and install ruby-build
git clone git://github.com/sstephenson/ruby-build.git /usr/local/src/ruby-build
cd /usr/local/src/ruby-build
./install.sh

# install ruby
cd /usr/local
ruby-build 1.9.3-p194 /usr/local/ruby-1.9.3-194

# setup ruby as default ruby using alternatives
# See `man update-alternatives` for information on how to switch between 
# versions of ruby. You can either manually switch between them or
# assign each install a priority that will automatically determine which
# version should be used.
update-alternatives --install /usr/local/ruby ruby /usr/local/ruby-1.9.3-194 0

# OR, just symlink the installed ruby to /usr/local/ruby. Pretty much the same
# effect, and a little more straightforward
ln -s ruby-1.9.3-194 ruby

# now, install bundler for use by capistrano below
/usr/local/ruby/bin/gem install bundler

ruby.sh

# Ruby initialization script (sh)
# Place this in /etc/profile.d

# Fedora is notorious for being late with updates to ruby versions.
# This is a modified version of the qt script to apend the bin paths
# to the PATH and set the lib/include directories.

# I used ruby-build https://github.com/sstephenson/ruby-build to install
# the rubies to /usr/local/ruby-xxx and used alternatives to install one
# as the current one.  This script is meant to append the alternative
# maintained path (/usr/local/ruby/bin) to the PATH variable so that the
# right version of ruby and any installed gems commands are correctly
# found. With this, the system ruby packages are no longer needed

if [ -z "${RUBYDIR}" ]; then

    if [ -d "/usr/local/ruby" ]; then

        RUBYDIR="/usr/local/ruby"

        if ! echo ${PATH} | /bin/grep -q $RUBYDIR/bin ; then
            PATH=$RUBYDIR/bin:${PATH}
        fi

        RUBYINC="$RUBYDIR/include"
        RUBYLIB="$RUBYDIR/lib"

        export RUBYDIR RUBYINC RUBYLIB PATH

    fi

fi