Groom your app’s Ruby environment with rbenv.
Use rbenv to pick a Ruby version for your application and guarantee that your development environment matches production. Put rbenv to work with Bundler for painless Ruby upgrades and bulletproof deployments.
Powerful in development. Specify your app's Ruby version once, in a single file. Keep all your teammates on the same page. No headaches running apps on different versions of Ruby. Just Works™ from the command line and with app servers like Pow. Override the Ruby version anytime: just set an environment variable.
Rock-solid in production. Your application's executables are its
interface with ops. With rbenv and Bundler
you'll never again need to
cd in a cron job or Chef recipe to
ensure you've selected the right runtime. The Ruby version
dependency lives in one place—your app—so upgrades and rollbacks are
atomic, even when you switch versions.
One thing well. rbenv is concerned solely with switching Ruby versions. It's simple and predictable. A rich plugin ecosystem lets you tailor it to suit your needs. Compile your own Ruby versions, or use the ruby-build plugin to automate the process. Specify per-application environment variables with rbenv-vars. See more plugins on the wiki.
Table of Contents
- How It Works
- Command Reference
How It Works
At a high level, rbenv intercepts Ruby commands using shim
executables injected into your
PATH, determines which Ruby version
has been specified by your application, and passes your commands along
to the correct Ruby installation.
When you run a command like
rake, your operating system
searches through a list of directories to find an executable file with
that name. This list of directories lives in an environment variable
PATH, with each directory in the list separated by a colon:
PATH are searched from left to right, so a matching
executable in a directory at the beginning of the list takes
precedence over another one at the end. In this example, the
/usr/local/bin directory will be searched first, then
rbenv works by inserting a directory of shims at the front of your
Through a process called rehashing, rbenv maintains shims in that
directory to match every Ruby command across every installed version
ruby, and so on.
Shims are lightweight executables that simply pass your command along
to rbenv. So with rbenv installed, when you run, say,
operating system will do the following:
- Search your
PATHfor an executable file named
- Find the rbenv shim named
rakeat the beginning of your
- Run the shim named
rake, which in turn passes the command along to rbenv
Choosing the Ruby Version
When you execute a shim, rbenv determines which Ruby version to use by reading it from the following sources, in this order:
RBENV_VERSIONenvironment variable, if specified. You can use the
rbenv shellcommand to set this environment variable in your current shell session.
.ruby-versionfile in the current directory, if present. You can modify the current directory's
.ruby-versionfile with the
.ruby-versionfile found by searching each parent directory until reaching the root of your filesystem, if any.
~/.rbenv/versionfile. You can modify this file using the
rbenv globalcommand. If the global version file is not present, rbenv assumes you want to use the "system" Ruby—i.e. whatever version would be run if rbenv weren't in your path.
Locating the Ruby Installation
Once rbenv has determined which version of Ruby your application has specified, it passes the command along to the corresponding Ruby installation.
Each Ruby version is installed into its own directory under
~/.rbenv/versions. For example, you might have these versions
Version names to rbenv are simply the names of the directories in
Compatibility note: rbenv is incompatible with RVM. Please make sure to fully uninstall RVM and remove any references to it from your shell initialization files before installing rbenv.
If you're on Mac OS X, consider installing with Homebrew.
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
$ git clone https://github.com/sstephenson/rbenv.git ~/.rbenv
$PATHfor access to the
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
Ubuntu note: Modify your
Zsh note: Modify your
~/.zshrcfile instead of
rbenv initto your shell to enable shims and autocompletion.
$ echo 'eval "$(rbenv init -)"' >> ~/.bash_profile
Same as in previous step, use
Restart your shell as a login shell so the path changes take effect. You can now begin using rbenv.
$ exec $SHELL -l
Install ruby-build, which provides an
rbenv installcommand that simplifies the process of installing new Ruby versions.
$ rbenv install 1.9.3-p327
As an alternative, you can download and compile Ruby yourself into
Rebuild the shim executables. You should do this any time you install a new Ruby executable (for example, when installing a new Ruby version, or when installing a gem that provides a command).
$ rbenv rehash
If you've installed rbenv manually using git, you can upgrade your installation to the cutting-edge version at any time.
$ cd ~/.rbenv $ git pull
To use a specific release of rbenv, check out the corresponding tag:
$ cd ~/.rbenv $ git fetch $ git checkout v0.3.0
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
To later update these installs, use
upgrade instead of
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
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
Installs autocompletion. This is entirely optional but pretty useful. Sourcing
~/.rbenv/completions/rbenv.bashwill set that up. There is also a
~/.rbenv/completions/rbenv.zshfor Zsh users.
Rehashes shims. From time to time you'll need to rebuild your shim files. Doing this automatically makes sure everything is up to date. You can always run
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 shellpossible. The sh dispatcher doesn't do anything crazy like override
cdor hack your shell prompt, but if for some reason you need
rbenvto be a real script rather than a shell function, you can safely skip it.
rbenv init - for yourself to see exactly what happens under the
Uninstalling Ruby Versions
As time goes on, Ruby versions you install will accumulate in your
To remove old Ruby versions, simply
rm -rf the directory of the
version you want to remove. You can find the directory of a particular
Ruby version with the
rbenv prefix command, e.g.
rbenv prefix 1.8.7-p357.
The ruby-build plugin
rbenv uninstall command to automate the removal
rbenv command delegates to subcommands based on its
first argument. The most common subcommands are:
Sets a local application-specific Ruby version by writing the version
name to a
.ruby-version file in the current directory. This version
overrides the global version, and can be overridden itself by setting
RBENV_VERSION environment variable or with the
$ rbenv local 1.9.3-p327
When run without a version number,
rbenv local reports the currently
configured local version. You can also unset the local version:
$ rbenv local --unset
Previous versions of rbenv stored local version specifications in a
.rbenv-version. For backwards compatibility, rbenv will
read a local version specified in an
.rbenv-version file, but a
.ruby-version file in the same directory will take precedence.
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 an application-specific
.ruby-version file, or by
RBENV_VERSION environment variable.
$ rbenv global 1.8.7-p352
The special version name
system tells rbenv to use the system Ruby
(detected by searching your
When run without a version number,
rbenv global reports the
currently configured global version.
Sets a shell-specific Ruby version by setting the
environment variable in your shell. This version overrides
application-specific versions and the global version.
$ rbenv shell jruby-1.7.1
When run without a version number,
rbenv shell reports the current
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-1.7.1
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-p327 (set by /Users/sam/.rbenv/version) jruby-1.7.1 rbx-1.2.4 ree-1.8.7-2011.03
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/.ruby-version)
Installs shims for all Ruby executables 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 commands.
$ rbenv rehash
Displays the full path to the executable that rbenv will invoke when you run the given command.
$ rbenv which irb /Users/sam/.rbenv/versions/1.9.3-p327/bin/irb
Lists all Ruby versions with the given command installed.
$ rbenv whence rackup 1.9.3-p327 jruby-1.7.1 ree-1.8.7-2011.03
The rbenv source code is hosted on GitHub. It's clean, modular, and easy to understand, even if you're not a shell hacker.
Tests are executed using Bats:
$ bats test $ bats test/<file>.bats
Please feel free to submit pull requests and file bugs on the issue tracker.
0.4.0 (January 4, 2013)
- rbenv now prefers
.rbenv-versionfiles for specifying local application-specific versions. The
.ruby-versionfile has the same format as
.rbenv-versionbut is compatible with other Ruby version managers.
ruby-local-execand moved its functionality into the standard
rubyshim. See the ruby-local-exec wiki page for upgrade instructions.
- Modified shims to include the full path to rbenv so that they can be
invoked without having rbenv's bin directory in the
- Sped up
rbenv initby avoiding rbenv reinitialization and by using a simpler indexing approach. (Users of chef-rbenv should upgrade to the latest version to fix a compatibility issue.)
rbenv helpso that usage and documentation is stored as a comment in each subcommand, enabling plugin commands to hook into the help system.
- Added support for full completion of the command line, not just the first argument.
- Updated installation instructions for Zsh and Ubuntu users.
rbenv prefixwith system Ruby versions.
rbenv execto avoid prepending the system Ruby location to
$PATHto fix issues running system Ruby commands that invoke other commands.
rbenv rehashto ensure it exits with a 0 status code under normal operation, and to ensure outdated shims are removed first when rehashing.
rbenv rehashto run
hash -rafterwards, when shell integration is enabled, to ensure the shell's command cache is cleared.
- Removed use of the
+=operator to support older versions of Bash.
- Adjusted non-bare
rbenv versionsoutput to include
system, if present.
- Improved documentation for installing and uninstalling Ruby versions.
rbenv versionsnot to display a warning if the currently specified version doesn't exist.
- Fixed an instance of local variable leakage in the
rbenvshell function wrapper.
rbenv shellto ensure it exits with a non-zero status on failure.
rbenv --versionfor printing the current version of rbenv.
/usr/lib/rbenv/hooksto the plugin hook search path.
rbenv whichto account for path entries with spaces.
rbenv initto accept option arguments in any order.
0.3.0 (December 25, 2011)
- Added an
rbenv rootcommand 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
- Fixed an issue with calling
readlinkfor paths with spaces.
- Changed Zsh initialization code to install completion hooks only for interactive shells.
- Added preliminary support for ksh.
rbenv rehashcreates 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
- Added a
rbenv initfor skipping the automatic rehash when opening a new shell.
0.2.1 (October 1, 2011)
- Changed the
rbenvcommand to ensure that
RBENV_DIRis always an absolute path. This fixes an issue where Ruby scripts using the
ruby-local-execwrapper would go into an infinite loop when invoked with a relative path from the command line.
0.2.0 (September 28, 2011)
rbenv local. The
set-commands are deprecated and will be removed in the next major release.
- rbenv now uses
- Added a
ruby-local-execcommand which can be used in shebangs in place of
#!/usr/bin/env rubyto properly set the project-specific Ruby version regardless of current working directory.
- Fixed an issue with
rbenv rehashwhen 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 shellcommand for conveniently setting the
- Added support for storing rbenv versions and shims in directories
- Added support for debugging rbenv via
set -xwhen the
$RBENV_DEBUGenvironment 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/pluginsas documented in issue #102.
/usr/local/etc/rbenv.dto the list of directories searched for rbenv hooks.
- Added support for an
$RBENV_DIRenvironment 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
- Made the
rbenv rehashcommand operate atomically.
- Modified the
rbenv initscript to automatically run
rbenv rehashso 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
-efrom the shebang in favor of
set -eat 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.
(The MIT license)
Copyright (c) 2013 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.