to update ubuntu 12.04 default ruby installation that is available for all users

i.e. 1.8 does not support JSON by default (dumb)

sudo apt-get install ruby1.9.3

sudo update-alternatives --config ruby

ruby version manager

RVM is a command-line tool: install, manage, and work with multiple ruby environments from interpreters to sets of gems.

as your normal user (not root!), BUT ha ha ha, a normal user that has SUDO

curl -L https://get.rvm.io | bash -s stable # installs RVM, remove -s stable for bleeding edge rvm -v # version 1.22.19

rvm autolibs read-fail # not require sudo source ~/.rvm/scripts/rvm rvm install 2.0.0 Searching for binary rubies, this might take some time. Checking requirements for ubuntu. Missing required packages: gawk, g++, gcc, make, libc6-dev, libreadline6-dev, zlib1g-dev, libssl-dev, libsqlite3-dev, sqlite3, autoconf, libgdbm-dev, libncurses5-dev, automake, libtool, bison, pkg-config, libffi-dev.

RVM autolibs is now configured with mode '2' => 'check and stop if missing',
please run `rvm autolibs enable` to let RVM do its job or run and read `rvm autolibs [help]` https://rvm.io/rvm/autolibs

rvm autolibs reset # require sudo

sudo apt-get update sudo apt-get install build-essential libgdbm-dev libncurses5-dev automake libtool bison libffi-dev gawk libreadline6-dev zlib1g-dev libssl-dev libsqlite3-dev sqlite3 pkg-config

rvm install 2.0.0

rvm use 2.0.0 --default

ERROR: RVM is not a function ... blah blah you should use sudo or modify .bash_profile or blah blah

vi ~/.bashrc # add this code to the end

if test -f ~/.rvm/scripts/rvm; then [ "$(type -t rvm)" = "function" ] || source ~/.rvm/scripts/rvm fi

. ~/.bashrc

rvm use 2.0.0 --default Using /home/USERNAME/.rvm/gems/ruby-2.0.0-p247

ruby -v which ruby

echo "gem: --no-ri --no-rdoc" > ~/.gemrc # do not install documentation for each package locally

http://gorails.com/setup/ubuntu

gem query --local

*** LOCAL GEMS ***

bundler (1.3.5)
bundler-unload (1.0.1)
chef (11.6.0)
erubis (2.7.0)
highline (1.6.19)
ipaddress (0.8.0)
json (1.7.7)
mime-types (1.23)
mixlib-authentication (1.3.0)
mixlib-cli (1.3.0)
mixlib-config (1.1.2)
mixlib-log (1.6.0)
mixlib-shellout (1.2.0)
net-ssh (2.6.8)
net-ssh-gateway (1.2.0)
net-ssh-multi (1.1)
ohai (6.18.0)
rake (10.1.0)
rest-client (1.6.7)
rubygems-bundler (1.2.2)
rvm (1.11.3.8)
systemu (2.5.2)
yajl-ruby (1.1.0)

vi ~/.bashrc source ~/.rvm/scripts/rvm

OTHER MAYBE UNECCESSARY INSTRUCTIONS

curl -L https://get.rvm.io | bash -s -- --ignore-dotfiles

• First you need to add all users that will be using rvm to 'rvm' group, and logout - login again, anyone using rvm will be operating with umask u=rwx,g=rwx,o=rx.

• To start using RVM you need to run source /etc/profile.d/rvm.sh in all your open shell windows, in rare cases you need to reopen all shell windows.

usermod -aG rvm ubuntu

echo "source $HOME/.rvm/scripts/rvm" >> ~/.bash_profile

hack fix: echo "source /home/ubuntu/.rvm/scripts/rvm" >> /home/ubuntu/.bashrc

after rebooting or logout/login verify with:

type rvm | head -n 1 # rvm is a function

if it fails, try this and then try again: source ~/.rvm/scripts/rvm

rvm requirements rvm install 2.0