chruby

Changes the current Ruby.

Features

• 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.

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 by default.
• Does not require write-access to the Ruby directory in order to install gems.

Install

wget -O chruby-0.3.4.tar.gz https://github.com/postmodern/chruby/archive/v0.3.4.tar.gz
tar -xzvf chruby-0.3.4.tar.gz
cd chruby-0.3.4/
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 https://raw.github.com/postmodern/chruby/master/pkg/chruby-0.3.4.tar.gz.asc
gpg --verify chruby-0.3.4.tar.gz.asc chruby-0.3.4.tar.gz

setup.sh

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

sudo ./scripts/setup.sh

Homebrew

chruby can also be installed with homebrew:

brew install chruby

Arch Linux

chruby is already included in the AUR:

yaourt -S chruby

Rubies

Manually

Chruby provides detailed instructions for installing additional Rubies:

• MRI
• JRuby
• Rubinius

ruby-build

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

Configuration

Add the following to the /etc/profile.d/chruby.sh, ~/.bashrc or ~/.zshrc file:

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

By default chruby will search for Rubies installed into /opt/rubies/ or ~/.rubies/. For non-standard installation locations, simply set the RUBIES variable:

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

Migrating

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

System Wide

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

[ -n "$BASH_VERSION" ] || [ -n "$ZSH_VERSION" ] || return

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

Auto-Switching

If you want chruby to auto-switch the current version of Ruby when you cd between your different projects, load auto.sh after chruby.sh:

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

Default Ruby

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

chruby ruby-1.9

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

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

Integration

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

• Emacs
• Cron
• Capistrano
• Pow

Examples

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

Alternatives

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

* Deprecated in favor of chruby.

Endorsements

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

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

Credits

• mpapis for reviewing the code.
• havenn for handling the homebrew formula.
• #bash, #zsh, #machomebrew for answering all my questions.