Simple Ruby Version Management: rbenv
rbenv lets you easily switch between multiple versions of Ruby. It's simple, unobtrusive, and follows the UNIX tradition of single-purpose tools that do one thing well.
rbenv does…
- Let you change the global Ruby version on a per-user basis.
- Provide support for per-project Ruby versions.
- Allow you to override the Ruby version with an environment variable.
In contrast with rvm, rbenv does not…
- Need to be loaded into your shell. Instead, rbenv's shim
approach works by adding a directory to your
$PATH
. - Override shell commands like
cd
. That's dangerous and error-prone. - Have a configuration file. There's nothing to configure except which version of Ruby you want to use.
- Install Ruby. You can build and install Ruby yourself, or use ruby-build to automate the process.
- Manage gemsets. Bundler is a better way to manage application dependencies. If you have projects that are not yet using Bundler you can install the rbenv-gemset plugin.
- Require changes to Ruby libraries for compatibility. The
simplicity of rbenv means as long as it's in your
$PATH
, nothing else needs to know about it. - Prompt you with warnings when you switch to a project. Instead of executing arbitrary code, rbenv reads just the version name from each project. There's nothing to "trust."
Table of Contents
1 How It Works
rbenv operates on the per-user directory ~/.rbenv
. Version names in
rbenv correspond to subdirectories of ~/.rbenv/versions
. For
example, you might have ~/.rbenv/versions/1.8.7-p354
and
~/.rbenv/versions/1.9.3-rc1
.
Each version is a working tree with its own binaries, like
~/.rbenv/versions/1.8.7-p354/bin/ruby
and
~/.rbenv/versions/1.9.3-rc1/bin/irb
. rbenv makes shim binaries
for every such binary across all installed versions of Ruby.
These shims are simple wrapper scripts that live in ~/.rbenv/shims
and detect which Ruby version you want to use. They insert the
directory for the selected version at the beginning of your $PATH
and then execute the corresponding binary.
Because of the simplicity of the shim approach, all you need to use
rbenv is ~/.rbenv/shims
in your $PATH
.
2 Installation
Compatibility note: rbenv is incompatible with rvm. Things will
appear to work until you try to install a gem. The problem is that
rvm actually overrides the gem
command with a shell function!
Please remove any references to rvm before using rbenv.
2.1 Basic GitHub Checkout
This will get you going with the latest version of rbenv and make it easy to fork and contribute any changes back upstream.
-
Check out rbenv into
~/.rbenv
.$ cd $ git clone git://github.com/sstephenson/rbenv.git .rbenv
-
Add
~/.rbenv/bin
to your$PATH
for access to therbenv
command-line utility.$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
Zsh note: Modifiy your
~/.zshenv
file instead of~/.bash_profile
. -
Add rbenv init to your shell to enable shims and autocompletion.
$ echo 'eval "$(rbenv init -)"' >> ~/.bash_profile
Zsh note: Modifiy your
~/.zshenv
file instead of~/.bash_profile
. -
Restart your shell so the path changes take effect. You can now begin using rbenv.
$ exec $SHELL
-
Install Ruby versions into
~/.rbenv/versions
. For example, to install Ruby 1.9.2-p290, download and unpack the source, then run:$ ./configure --prefix=$HOME/.rbenv/versions/1.9.2-p290 $ make $ make install
The ruby-build project provides an
rbenv install
command that simplifies the process of installing new Ruby versions to:$ rbenv install 1.9.2-p290
-
Rebuild the shim binaries. You should do this any time you install a new Ruby binary (for example, when installing a new Ruby version, or when installing a gem that provides a binary).
$ rbenv rehash
2.1.1 Upgrading
If you've installed rbenv using the instructions above, you can upgrade your installation at any time using git.
To upgrade to the latest development version of rbenv, use git pull
:
$ cd ~/.rbenv
$ git pull
To upgrade to a specific release of rbenv, check out the corresponding tag:
$ cd ~/.rbenv
$ git fetch
$ git tag
v0.1.0
v0.1.1
v0.1.2
v0.2.0
$ git checkout v0.2.0
2.2 Homebrew on Mac OS X
You can also install rbenv using the Homebrew package manager on Mac OS X.
$ brew update
$ brew install rbenv
$ brew install ruby-build
The same commands can be used for upgrading.
Afterwards you'll still need to add eval "$(rbenv init -)"
to your
profile as stated in the caveats. You'll only ever have to do this
once.
2.3 Neckbeard Configuration
Skip this section unless you must know what every line in your shell profile is doing.
rbenv init
is the only command that crosses the line of loading
extra commands into your shell. Coming from rvm, some of you might be
opposed to this idea. Here's what rbenv init
actually does:
-
Sets up your shims path. This is the only requirement for rbenv to function properly. You can do this by hand by prepending
~/.rbenv/shims
to your$PATH
. -
Installs autocompletion. This is entirely optional but pretty useful. Sourcing
~/.rbenv/completions/rbenv.bash
will set that up. There is also a~/.rbenv/completions/rbenv.zsh
for Zsh users. -
Rehashes shims. From time to time you'll need to rebuild your shim files. Doing this on init makes sure everything is up to date. You can always run
rbenv rehash
manually. -
Installs the sh dispatcher. This bit is also optional, but allows rbenv and plugins to change variables in your current shell, making commands like
rbenv shell
possible. The sh dispatcher doesn't do anything crazy like overridecd
or hack your shell prompt, but if for some reason you needrbenv
to be a real script rather than a shell function, you can safely skip it.
Run rbenv init -
for yourself to see exactly what happens under the
hood.
3 Usage
Like git
, the rbenv
command delegates to subcommands based on its
first argument. The most common subcommands are:
3.1 rbenv global
Sets the global version of Ruby to be used in all shells by writing
the version name to the ~/.rbenv/version
file. This version can be
overridden by a per-project .rbenv-version
file, or by setting the
RBENV_VERSION
environment variable.
$ rbenv global 1.9.2-p290
The special version name system
tells rbenv to use the system Ruby
(detected by searching your $PATH
).
When run without a version number, rbenv global
reports the
currently configured global version.
3.2 rbenv local
Sets a local per-project Ruby version by writing the version name to
an .rbenv-version
file in the current directory. This version
overrides the global, and can be overridden itself by setting the
RBENV_VERSION
environment variable or with the rbenv shell
command.
$ rbenv local rbx-1.2.4
When run without a version number, rbenv local
reports the currently
configured local version. You can also unset the local version:
$ rbenv local --unset
3.3 rbenv shell
Sets a shell-specific Ruby version by setting the RBENV_VERSION
environment variable in your shell. This version overrides both
project-specific versions and the global version.
$ rbenv shell jruby-1.6.4
When run without a version number, rbenv shell
reports the current
value of RBENV_VERSION
. You can also unset the shell version:
$ rbenv shell --unset
Note that you'll need rbenv's shell integration enabled (step 3 of
the installation instructions) in order to use this command. If you
prefer not to use shell integration, you may simply set the
RBENV_VERSION
variable yourself:
$ export RBENV_VERSION=jruby-1.6.4
3.4 rbenv versions
Lists all Ruby versions known to rbenv, and shows an asterisk next to the currently active version.
$ rbenv versions
1.8.7-p352
1.9.2-p290
* 1.9.3-rc1 (set by /Users/sam/.rbenv/global)
jruby-1.6.4
rbx-1.2.4
ree-1.8.7-2011.03
3.5 rbenv version
Displays the currently active Ruby version, along with information on how it was set.
$ rbenv version
1.8.7-p352 (set by /Volumes/37signals/basecamp/.rbenv-version)
3.6 rbenv rehash
Installs shims for all Ruby binaries known to rbenv (i.e.,
~/.rbenv/versions/*/bin/*
). Run this command after you install a new
version of Ruby, or install a gem that provides binaries.
$ rbenv rehash
3.7 rbenv which
Displays the full path to the binary that rbenv will execute when you run the given command.
$ rbenv which irb
/Users/sam/.rbenv/versions/1.9.2-p290/bin/irb
3.8 rbenv whence
Lists all Ruby versions with the given command installed.
$ rbenv whence rackup
1.9.3-rc1
jruby-1.6.4
ree-1.8.7-2011.03
4 Development
The rbenv source code is hosted on GitHub. It's clean, modular, and easy to understand, even if you're not a shell hacker.
Please feel free to submit pull requests and file bugs on the issue tracker.
4.1 Version History
0.3.0 (December 25, 2011)
- Added an
rbenv root
command which prints the value of$RBENV_ROOT
, or the default root directory if it's unset. - Clarified Zsh installation instructions in the readme.
- Removed some redundant code in
rbenv rehash
. - Fixed an issue with calling
readlink
for paths with spaces. - Changed Zsh initialization code to install completion hooks only for interactive shells.
- Added preliminary support for ksh.
rbenv rehash
creates or removes shims only when necessary instead of removing and re-creating all shims on each invocation.- Fixed that
RBENV_DIR
, when specified, would be incorrectly expanded to its parent directory. - Removed the deprecated
set-default
andset-local
commands. - Added a
--no-rehash
option torbenv init
for skipping the automatic rehash when opening a new shell.
0.2.1 (October 1, 2011)
- Changed the
rbenv
command to ensure thatRBENV_DIR
is always an absolute path. This fixes an issue where Ruby scripts using theruby-local-exec
wrapper would go into an infinite loop when invoked with a relative path from the command line.
0.2.0 (September 28, 2011)
- Renamed
rbenv set-default
torbenv global
andrbenv set-local
torbenv local
. Theset-
commands are deprecated and will be removed in the next major release. - rbenv now uses
greadlink
on Solaris. - Added a
ruby-local-exec
command which can be used in shebangs in place of#!/usr/bin/env ruby
to properly set the project-specific Ruby version regardless of current working directory. - Fixed an issue with
rbenv rehash
when no binaries are present. - Added support for
rbenv-sh-*
commands, which run inside the current shell instead of in a child process. - Added an
rbenv shell
command for conveniently setting the$RBENV_VERSION
environment variable. - Added support for storing rbenv versions and shims in directories
other than
~/.rbenv
with the$RBENV_ROOT
environment variable. - Added support for debugging rbenv via
set -x
when the$RBENV_DEBUG
environment variable is set. - Refactored the autocompletion system so that completions are now built-in to each command and shared between bash and Zsh.
- Added support for plugin bundles in
~/.rbenv/plugins
as documented in issue #102. - Added
/usr/local/etc/rbenv.d
to the list of directories searched for rbenv hooks. - Added support for an
$RBENV_DIR
environment variable which defaults to the current working directory for specifying where rbenv searches for local version files.
0.1.2 (August 16, 2011)
- Fixed rbenv to be more resilient against nonexistent entries in
$PATH
. - Made the
rbenv rehash
command operate atomically. - Modified the
rbenv init
script to automatically runrbenv rehash
so that shims are recreated whenever a new shell is opened. - Added initial support for Zsh autocompletion.
- Removed the dependency on egrep for reading version files.
0.1.1 (August 14, 2011)
- Fixed a syntax error in the
rbenv help
command. - Removed
-e
from the shebang in favor ofset -e
at the top of each file for compatibility with operating systems that do not support more than one argument in the shebang.
0.1.0 (August 11, 2011)
- Initial public release.
4.2 License
(The MIT license)
Copyright (c) 2011 Sam Stephenson
Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.