Install the Ruby version manager rbenv and ruby-build to allow you to install Ruby versions

install_rbenv.sh

#!/usr/bin/env bash

set -eo pipefail
# -e exit if any command returns non-zero status code
# -o pipefail force pipelines to fail on first non-zero status code

FATAL="\\033[1;31mFATAL\\033[0m"
WARNING="\\033[1;33mWARNING\\033[0m"
PASS="\\033[1;32mPASS\\033[0m"
INFO="\\033[1;36mINFO\\033[0m"

function install_rbenv {

	# Install rbenv 
	# Install ruby-build

	echo -e "[$INFO] Installing rbenv and ruby-build"

	# if apt install rbenv ; then
	# 	# The apt package is outdated 
	# 	# https://github.com/rbenv/rbenv/issues/1068
	# 	echo -e "[${PASS}] Installed rbenv"
	# else
	# 	echo -e "[${FATAL}] Failed to install rbenv"
	# 	exit 1
	# fi

	echo -e "[${INFO}] Creating ${HOME}/.rbenv"
	if mkdir -p "${HOME}/.rbenv" ; then
		echo -e "[${PASS}] Created ${HOME}/.rbenv"
	else
		echo -e "[${FATAL}] Failed to create ${HOME}/.rbenv"
	fi

	echo -e "[${INFO}] Cloning rbenv from Github"
	if git clone --quiet https://github.com/rbenv/rbenv.git "${HOME}/.rbenv" ; then
		echo -e "[${PASS}] Cloned rbenv into ${HOME}/.rbenv"
	else
		echo -e "[${FATAL}] Failed to clone rbenv into ${HOME}/.rbenv"
		exit 1
	fi
	
	echo -e "[${INFO}] Attempting to compile dynamic bash extension"
	
	# Enter subshell
	(
	# TODO: Capture errors and echo them if make/configure fails
	local configure_fail=""

	cd "$HOME/.rbenv" || exit

	if ./src/configure ; then 
		echo -e "[${PASS}] ./src/configure successful"
		configure_fail="false"
	else
		echo -e "[${FATAL}] Failed to compiled dynamic bash extension"
		configure_fail="true"
	fi

	if [[ "${configure_fail}" != "true" ]]; then
		if make --silent -C src ; then
			echo -e "[${PASS}] Sucessfully compiled dynamic bash extension"
		else
			echo -e "[${FATAL}] Failed to compiled dynamic bash extension"
			exit 1
		fi
	fi

	)
	# Exit subshell

	# Include rbenv binary directory in PATH
	if grep -q 'export PATH="$HOME/.rbenv/bin:$PATH"' "${HOME}/.bashrc" ; then
		echo -e "[${PASS}] "export PATH="$HOME/.rbenv/bin:$PATH"" already in '$HOME/.bashrc'"
	else
		echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> "$HOME/.bashrc"
		echo -e "[${PASS}] Added "export PATH="$HOME/.rbenv/bin:$PATH"" to '$HOME/.bashrc'"
	fi

	# Load rbenv automatically 
	echo 'eval "$(rbenv init -)"' >> "$HOME/.bashrc"



	# WTF is this shit?
	# Exit code is 0 but else condition triggers
	if ~/.rbenv/bin/rbenv init ; then 
		echo -e "[${PASS}] wooo"
		echo "Exit code: $?"
	else
		echo -e "[${FATAL}] boo"
		echo "Exit code: $?"
	fi



	# So that PATH changes take effect in the current shell
	# shellcheck disable=SC1090
	source "$HOME/.bashrc"

	# Install ruby-build

	echo -e "[$INFO] Installing ruby-build"

	if mkdir -p "$(rbenv root)/plugins" ; then
		echo -e "[${PASS}] Sucessfully created $(rbenv root)/plugins"
	else
		echo -e "[${FATAL}] Failed to create $(rbenv root)/plugins"
	fi

	echo -e "[${INFO}] Cloning ruby-build from Github"
	if git clone --quiet https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build ; then
		echo -e "[${PASS}] Cloned ruby-build into $(rbenv root)/plugins/ruby-build"
	else
		echo -e "[${FATAL}] Failed to clone ruby-build into $(rbenv root)/plugins/ruby-build"
		exit 1
	fi

	curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash

	# # shellcheck disable=SC2016
	# if grep -q 'eval $(rbenv init -)' "${HOME}/.bash_profile" ; then
	# 	echo -e "[${PASS}] 'eval \"$(rbenv init -)\"' already in ~/.bash_profile"
	# else
	# 	echo 'eval "$(rbenv init -)"' >> ~/.bash_profile
	# 	# shellcheck disable=SC1090
	# 	source "${HOME}"/.bash_profile
	# fi
}


function rbenv_install_ruby {

	if rbenv install -l | grep -q "${ruby_version}" ; then
		echo -e "[${PASS}] rbenv Ruby version already ${ruby_version}"
	else
		echo -e "[${INFO}] Installing Ruby ${ruby_version} via rbenv"
		if rbenv install "${ruby_version}" ; then
			echo -e "[${PASS}] Ruby ${ruby_version} installed via rbenv"
    		rvm use "${ruby_version}" -- default
    	else
    		echo -e "[${FATAL}] Failed to install Ruby ${ruby_version} via rbenv"
    		exit 1
    	fi
    fi

}

function main {

	ruby_version="2.3.0"

	install_rbenv
	rbenv_install_ruby
}

main "$@"