text: CHRUBY_VERSION="0.3.9"
  RUBIES=()
  
  for dir in "$PREFIX/opt/rubies" "$HOME/.rubies"; do
  	[[ -d "$dir" && -n "$(ls -A "$dir")" ]] && RUBIES+=("$dir"/*)
  done
  unset dir
  
  function chruby_reset()
  {
  	[[ -z "$RUBY_ROOT" ]] && return
  
  	PATH=":$PATH:"; PATH="${PATH//:$RUBY_ROOT\/bin:/:}"
  	[[ -n "$GEM_ROOT" ]] && PATH="${PATH//:$GEM_ROOT\/bin:/:}"
  
  	if (( UID != 0 )); then
  		[[ -n "$GEM_HOME" ]] && PATH="${PATH//:$GEM_HOME\/bin:/:}"
  
  		GEM_PATH=":$GEM_PATH:"
  		[[ -n "$GEM_HOME" ]] && GEM_PATH="${GEM_PATH//:$GEM_HOME:/:}"
  		[[ -n "$GEM_ROOT" ]] && GEM_PATH="${GEM_PATH//:$GEM_ROOT:/:}"
  		GEM_PATH="${GEM_PATH#:}"; GEM_PATH="${GEM_PATH%:}"
  
  		unset GEM_HOME
  		[[ -z "$GEM_PATH" ]] && unset GEM_PATH
  	fi
  
  	PATH="${PATH#:}"; PATH="${PATH%:}"
  	unset RUBY_ROOT RUBY_ENGINE RUBY_VERSION RUBYOPT GEM_ROOT
  	hash -r
  }
  
  function chruby_use()
  {
  	if [[ ! -x "$1/bin/ruby" ]]; then
  		echo "chruby: $1/bin/ruby not executable" >&2
  		return 1
  	fi
  
  	[[ -n "$RUBY_ROOT" ]] && chruby_reset
  
  	export RUBY_ROOT="$1"
  	export RUBYOPT="$2"
  	export PATH="$RUBY_ROOT/bin:$PATH"
  
  	eval "$(RUBYGEMS_GEMDEPS="" "$RUBY_ROOT/bin/ruby" - <<EOF
  puts "export RUBY_ENGINE=#{Object.const_defined?(:RUBY_ENGINE) ? RUBY_ENGINE : 'ruby'};"
  puts "export RUBY_VERSION=#{RUBY_VERSION};"
  begin; require 'rubygems'; puts "export GEM_ROOT=#{Gem.default_dir.inspect};"; rescue LoadError; end
  EOF
  )"
  	export PATH="${GEM_ROOT:+$GEM_ROOT/bin:}$PATH"
  
  	if (( UID != 0 )); then
  		export GEM_HOME="$HOME/.gem/$RUBY_ENGINE/$RUBY_VERSION"
  		export GEM_PATH="$GEM_HOME${GEM_ROOT:+:$GEM_ROOT}${GEM_PATH:+:$GEM_PATH}"
  		export PATH="$GEM_HOME/bin:$PATH"
  	fi
  
  	hash -r
  }
  
  function chruby()
  {
  	case "$1" in
  		-h|--help)
  			echo "usage: chruby [RUBY|VERSION|system] [RUBYOPT...]"
  			;;
  		-V|--version)
  			echo "chruby: $CHRUBY_VERSION"
  			;;
  		"")
  			local dir ruby
  			for dir in "${RUBIES[@]}"; do
  				dir="${dir%%/}"; ruby="${dir##*/}"
  				if [[ "$dir" == "$RUBY_ROOT" ]]; then
  					echo " * ${ruby} ${RUBYOPT}"
  				else
  					echo "   ${ruby}"
  				fi
  
  			done
  			;;
  		system) chruby_reset ;;
  		*)
  			local dir ruby match
  			for dir in "${RUBIES[@]}"; do
  				dir="${dir%%/}"; ruby="${dir##*/}"
  				case "$ruby" in
  					"$1")	match="$dir" && break ;;
  					*"$1"*)	match="$dir" ;;
  				esac
  			done
  
  			if [[ -z "$match" ]]; then
  				echo "chruby: unknown Ruby: $1" >&2
  				return 1
  			fi
  
  			shift
  			chruby_use "$match" "$*"
  			;;
  	esac
  }
  