chruby

Simple Ruby switcher.

Features

Simply modifies $PATH.
Correctly sets $GEM_HOME and $GEM_PATH.
- Users: gems are installed into ~/.gem/$ruby/$version.
- Root: gems are installed directly into /path/to/$ruby/$gemdir.
Adds RubyGems bin/ directories to $PATH.
Optionally sets $RUBYOPT is a second argument is given.
Additionally sets $RUBY, $RUBY_ENGINE, $RUBY_VERSION and $GEM_ROOT.
Calls hash -r to clear the command-lookup hash-table.
Fuzzy matching of Rubies by name.
Defaults to the system Ruby.
Small (~80 LOC).

Anti-Features

Does not hook cd.
Does not install executable shims.
Does not require Rubies be installed into your home directory.
Does not automatically switch Rubies upon login or when changing directories.
Does not require write-access to the Ruby directory in order to install gems.

Install

wget http://cloud.github.com/downloads/postmodern/chruby/chruby-0.1.0.tar.bz2
tar -xjvf chruby-0.1.0.tar.bz2
cd chrub-0.1.0/
make install

PGP

All releases are PGP signed for security. Instructions on how to import my PGP key can be found on my blog. To verify that a release was not tampered with:

wget http://cloud.github.com/downloads/postmodern/chruby/chruby-0.1.0.tar.bz2.asc
gpg --verify chruby-0.1.0.tar.bz2.asc chruby-0.1.0.tar.bz2

Configuration

Add the following lines to your ~/.bashrc or ~/.profile file:

. /usr/local/etc/profile.d/chruby.sh

RUBIES=~/src/{ruby,jruby,rubinius}*

System Wide

Create a /etc/profile.d/chruby.sh file, containing the following:

. /usr/local/etc/profile.d/chruby.sh

RUBIES=(
  /usr/local/ruby-1.8.7-p370
  /usr/local/ruby-1.9.3-p194
  /usr/local/jruby-1.6.7.2
  /usr/local/rubinius
)

Examples

List available Rubies:

$ chruby
   ruby-1.8.7-p370
   ruby-1.9.3-p194
   jruby-1.6.7.2
   rubinius

Select a Ruby:

$ chruby 1.8
$ chruby
 * ruby-1.8.7-p370
   ruby-1.9.3-p194
   jruby-1.6.7.2
   rubinius
$ echo $PATH
/home/hal/.gem/ruby/1.8.7/bin:/usr/local/ruby-1.8.7-p370/lib/ruby/gems/1.8/bin:/usr/local/ruby-1.8.7-p370/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/hal/bin
$ echo $GEM_HOME
/home/hal/.gem/ruby/1.8.7
$ echo $GEM_PATH
/home/hal/.gem/ruby/1.8.7:/usr/local/ruby-1.8.7-p370/lib/ruby/gems/1.8

Switch to JRuby in 1.9 mode:

$ chruby jruby --1.9
$ ruby -v
jruby 1.6.7.2 (ruby-1.9.2-p312) (2012-05-01 26e08ba) (OpenJDK 64-Bit Server VM 1.6.0_24) [linux-amd64-java]

Switch back to system Ruby:

$ chruby system
$ echo $PATH
/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/sbin:/home/hal/bin

Switch to an arbitrary Ruby on the fly:

$ chruby_use /path/to/ruby

mpapis/chruby