Changes the current Ruby.

• Updates $PATH.
  • Also adds RubyGems bin/ directories to $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.
• Additionally sets $RUBY_ROOT, $RUBY_ENGINE, $RUBY_VERSION and $GEM_ROOT.
• Optionally sets $RUBYOPT if second argument is given.
• Calls hash -r to clear the command-lookup hash-table.
• Fuzzy matching of Rubies by name.
• Defaults to the system Ruby.
• Optionally supports auto-switching and the .ruby-version file.
• Supports bash and zsh.
• Small (~90 LOC).
• Has tests.

• Does not hook cd.
• Does not install executable shims.
• Does not require Rubies be installed into your home directory.
• Does not automatically switch Rubies by default.
• Does not require write-access to the Ruby directory in order to install gems.

wget -O chruby-0.3.8.tar.gz https://github.com/postmodern/chruby/archive/v0.3.8.tar.gz
tar -xzvf chruby-0.3.8.tar.gz
cd chruby-0.3.8/
sudo make install

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 https://raw.github.com/postmodern/chruby/master/pkg/chruby-0.3.8.tar.gz.asc
gpg --verify chruby-0.3.8.tar.gz.asc chruby-0.3.8.tar.gz

chruby also includes a setup.sh script, which installs chruby and the latest releases of Ruby, JRuby and Rubinius. Simply run the script as root or via sudo:

sudo ./scripts/setup.sh

chruby can also be installed with homebrew:

brew install chruby

Or the absolute latest chruby can be installed from source:

brew install chruby --HEAD

chruby is already included in the AUR:

yaourt -S chruby

chruby is included in the official FreeBSD ports collection:

cd /usr/ports/devel/chruby/ && make install clean

Chruby provides detailed instructions for installing additional Rubies:

• Ruby
• JRuby
• Rubinius
• MagLev

You can also use ruby-install to install additional Rubies:

Installing to /opt/rubies or ~/.rubies:

ruby-install ruby
ruby-install jruby
ruby-install rubinius
ruby-install maglev

You can also use ruby-build to install additional Rubies:

Installing to /opt/rubies:

ruby-build 1.9.3-p392 /opt/rubies/ruby-1.9.3-p392
ruby-build jruby-1.7.3 /opt/rubies/jruby-1.7.3
ruby-build rbx-2.0.0-rc1 /opt/rubies/rubinius-2.0.0-rc1
ruby-build maglev-1.0.0 /opt/rubies/maglev-1.0.0

Add the following to the ~/.bashrc or ~/.zshrc file:

source /usr/local/share/chruby/chruby.sh

If you wish to enable chruby system-wide, add the following to /etc/profile.d/chruby.sh:

if [ -n "$BASH_VERSION" ] || [ -n "$ZSH_VERSION" ]; then
  source /usr/local/share/chruby/chruby.sh
  ...
fi

This will prevent chruby from accidentally being loaded by /bin/sh, which is not always the same as /bin/bash.

When chruby is first loaded by the shell, it will auto-detect Rubies installed in /opt/rubies/ and ~/.rubies/. After installing new Rubies, you must restart the shell before chruby can recognize them.

For Rubies installed in non-standard locations, simply append their paths to the RUBIES variable:

source /usr/local/share/chruby/chruby.sh

RUBIES+=(
  /opt/jruby-1.7.0
  "$HOME/src/rubinius"
)

If you are migrating from another Ruby manager, set RUBIES accordingly:

RUBIES+=(~/.rvm/rubies/*)

RUBIES+=(~/.rbenv/versions/*)

RUBIES+=(~/.rbfu/rubies/*)

If you want chruby to auto-switch the current version of Ruby when you cd between your different projects, simply load auto.sh in ~/.bashrc or ~/.zshrc:

source /usr/local/share/chruby/chruby.sh
source /usr/local/share/chruby/auto.sh

chruby will check the current and parent directories for a .ruby-version file. Other Ruby switchers also understand this file: https://gist.github.com/1912050

If you want to automatically run the version of a gem executable specified in your project's Gemfile, try rubygems-bundler.

If you wish to set a default Ruby, simply call chruby in ~/.bash_profile or ~/.zprofile:

chruby ruby-1.9

If you have enabled auto-switching, simply create a .ruby-version file:

echo "ruby-1.9" > ~/.ruby-version

Gems installed as a non-root user via gem install will be installed into ~/.gem/$ruby/X.Y.Z. By default, RubyGems will use the absolute path to the currently selected ruby for the shebang of any binstubs it generates. In some cases, this path may contain extra version information (e.g. ruby-2.0.0-p451). To mitigate potential problems when removing rubies, you can force RubyGems to generate binstubs with shebangs that will search for ruby in your $PATH by using gem install --env-shebang (or the equivalent short option -E). This parameter can also be added to your gemrc file.

For instructions on using chruby with other tools, please see the wiki:

• Capistrano
• Chef
• Cron
• Emacs
• Pow
• Puppet
• Sudo
• Vim

List available Rubies:

$ chruby
   ruby-1.9.3-p392
   jruby-1.7.0
   rubinius-2.0.0-rc1

Select a Ruby:

$ chruby 1.9.3
$ chruby
 * ruby-1.9.3-p392
   jruby-1.7.0
   rubinius-2.0.0-rc1
$ echo $PATH
/home/hal/.gem/ruby/1.9.3/bin:/opt/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1/bin:/opt/rubies/ruby-1.9.3-p392/bin:/usr/lib64/qt-3.3/bin:/usr/local/bin:/usr/bin:/bin:/usr/local/sbin:/usr/sbin:/home/hal/bin:/home/hal/bin
$ gem env
RubyGems Environment:
  - RUBYGEMS VERSION: 1.8.23
  - RUBY VERSION: 1.9.3 (2013-02-22 patchlevel 392) [x86_64-linux]
  - INSTALLATION DIRECTORY: /home/hal/.gem/ruby/1.9.3
  - RUBY EXECUTABLE: /opt/rubies/ruby-1.9.3-p392/bin/ruby
  - EXECUTABLE DIRECTORY: /home/hal/.gem/ruby/1.9.3/bin
  - RUBYGEMS PLATFORMS:
    - ruby
    - x86_64-linux
  - GEM PATHS:
     - /home/hal/.gem/ruby/1.9.3
     - /opt/rubies/ruby-1.9.3-p392/lib/ruby/gems/1.9.1
  - GEM CONFIGURATION:
     - :update_sources => true
     - :verbose => true
     - :benchmark => false
     - :backtrace => false
     - :bulk_threshold => 1000
     - "gem" => "--no-rdoc"
  - REMOTE SOURCES:
     - http://rubygems.org/

Switch to JRuby in 1.9 mode:

$ chruby jruby --1.9
$ ruby -v
jruby 1.7.0 (1.9.3p203) 2012-10-22 ff1ebbe on OpenJDK 64-Bit Server VM 1.7.0_09-icedtea-mockbuild_2012_10_17_15_53-b00 [linux-amd64]

Switch back to system Ruby:

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

Run a command under a Ruby with chruby-exec:

$ chruby-exec jruby -- gem update

Switch to an arbitrary Ruby on the fly:

$ chruby_use /path/to/ruby

After removing the chruby configuration:

$ sudo make uninstall

• RVM
• rbenv
• rbfu*
• ry
• ruby-version*

* Deprecated in favor of chruby.

yeah chruby is nice, does the limited thing of switching really good, the only hope it never grows

-- Michal Papis of RVM

I just looooove chruby For the first time I'm in total control of all aspects of my Ruby installation.

-- Marius Mathiesen

Written by Postmodern, it's basically the simplest possible thing that can work.

-- Steve Klabnik

So far, I'm a huge fan. The tool does what it advertises exactly and simply. The small feature-set is also exactly and only the features I need.

-- Patrick Brisbin

I wrote ruby-version; however, chruby is already what ruby-version wanted to be. I've deprecated ruby-version in favor of chruby.

-- Wil Moore III

• mpapis for reviewing the code.
• havenwood for handling the homebrew formula.
• zendeavor for style fixes.
• #bash, #zsh, #machomebrew for answering all my questions.