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
binstubs
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.
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 ruby or 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
called PATH, with each directory in the list separated by a colon:
/usr/local/bin:/usr/bin:/bin
Directories in 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 /usr/bin,
then /bin.
rbenv works by inserting a directory of shims at the front of your
PATH:
~/.rbenv/shims:/usr/local/bin:/usr/bin:/bin
Through a process called rehashing, rbenv maintains shims in that
directory to match every Ruby command across every installed version
of Ruby—irb, gem, rake, rails, ruby, and so on.
Shims are lightweight executables that simply pass your command along
to rbenv. So with rbenv installed, when you run, say, rake, your
operating system will do the following:
- Search your
PATHfor an executable file namedrake - Find the rbenv shim named
rakeat the beginning of yourPATH - Run the shim named
rake, which in turn passes the command along to rbenv
When you execute a shim, rbenv determines which Ruby version to use by reading it from the following sources, in this order:
-
The
RBENV_VERSIONenvironment variable, if specified. You can use therbenv shellcommand to set this environment variable in your current shell session. -
The first
.ruby-versionfile found by searching the directory of the script you are executing and each of its parent directories until reaching the root of your filesystem. -
The first
.ruby-versionfile found by searching the current working directory and each of its parent directories until reaching the root of your filesystem. You can modify the.ruby-versionfile in the current working directory with therbenv localcommand. -
The global
~/.rbenv/versionfile. You can modify this file using therbenv 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.
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
installed:
~/.rbenv/versions/1.8.7-p371/~/.rbenv/versions/1.9.3-p327/~/.rbenv/versions/jruby-1.7.1/
Version names to rbenv are simply the names of the directories in
~/.rbenv/versions.
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 macOS, we recommend installing rbenv with Homebrew.
-
Install rbenv.
$ brew install rbenv
Note that this also installs
ruby-build, so you'll be ready to install other Ruby versions out of the box. -
Set up rbenv in your shell.
$ rbenv init
Follow the printed instructions to set up rbenv shell integration.
-
Close your Terminal window and open a new one so your changes take effect.
-
Verify that rbenv is properly set up using this rbenv-doctor script:
$ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash Checking for `rbenv' in PATH: /usr/local/bin/rbenv Checking for rbenv shims in PATH: OK Checking `rbenv install' support: /usr/local/bin/rbenv-install (ruby-build 20170523) Counting installed Ruby versions: none There aren't any Ruby versions installed under `~/.rbenv/versions'. You can install Ruby versions like so: rbenv install 2.2.4 Checking RubyGems settings: OK Auditing installed plugins: OK
That's it! Installing rbenv includes ruby-build, so now you're ready to install some other Ruby versions using
rbenv install.To upgrade to the latest rbenv and update ruby-build with newly released Ruby versions, upgrade the Homebrew packages:
$ brew upgrade rbenv ruby-build
For a more automated install, you can use rbenv-installer. If you prefer a manual approach, follow the steps below.
This will get you going with the latest version of rbenv without needing a systemwide install.
-
Clone rbenv into
~/.rbenv.$ git clone https://github.com/rbenv/rbenv.git ~/.rbenvOptionally, try to compile dynamic bash extension to speed up rbenv. Don't worry if it fails; rbenv will still work normally:
$ cd ~/.rbenv && src/configure && make -C src -
Add
~/.rbenv/binto your$PATHfor access to therbenvcommand-line utility.-
For bash:
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bash_profile
-
For Ubuntu Desktop:
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
-
For Zsh:
$ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.zshrc
-
For Fish shell:
$ set -Ux fish_user_paths $HOME/.rbenv/bin $fish_user_paths
-
-
Set up rbenv in your shell.
$ ~/.rbenv/bin/rbenv initFollow the printed instructions to set up rbenv shell integration.
-
Restart your shell so that PATH changes take effect. (Opening a new terminal tab will usually do it.)
-
Verify that rbenv is properly set up using this rbenv-doctor script:
$ curl -fsSL https://github.com/rbenv/rbenv-installer/raw/master/bin/rbenv-doctor | bash Checking for `rbenv' in PATH: /usr/local/bin/rbenv Checking for rbenv shims in PATH: OK Checking `rbenv install' support: /usr/local/bin/rbenv-install (ruby-build 20170523) Counting installed Ruby versions: none There aren't any Ruby versions installed under `~/.rbenv/versions'. You can install Ruby versions like so: rbenv install 2.2.4 Checking RubyGems settings: OK Auditing installed plugins: OK
-
(Optional) Install ruby-build, which provides the
rbenv installcommand that simplifies the process of installing new Ruby versions.
If you've installed rbenv manually using Git, you can upgrade to the latest version by pulling from GitHub:
$ cd ~/.rbenv $ git pull
Skip this section unless you must know what every line in your shell profile is doing.
rbenv initis 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 whatrbenv initactually 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/shimsto your$PATH. -
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
rbenv rehashmanually. -
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 invasive like overridecdor hack your shell prompt, but if for some reason you needrbenvto 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.The
rbenv installcommand doesn't ship with rbenv out of the box, but is provided by the ruby-build project. If you installed it either as part of GitHub checkout process outlined above or via Homebrew, you should be able to:# list all available versions: $ rbenv install -l # install a Ruby version: $ rbenv install 2.0.0-p247
Alternatively to the
installcommand, you can download and compile Ruby manually as a subdirectory of~/.rbenv/versions/. An entry in that directory can also be a symlink to a Ruby version installed elsewhere on the filesystem. rbenv doesn't care; it will simply treat any entry in theversions/directory as a separate Ruby version.Once you've installed some Ruby versions, you'll want to install gems. First, ensure that the target version for your project is the one you want by checking
rbenv version(see Command Reference). Select another version usingrbenv local 2.0.0-p247, for example. Then, proceed to install gems as you normally would:$ gem install bundler
You don't need sudo to install gems. Typically, the Ruby versions will be installed and writeable by your user. No extra privileges are required to install gems.
Check the location where gems are being installed with
gem env:$ gem env home # => ~/.rbenv/versions/<ruby-version>/lib/ruby/gems/...As time goes on, Ruby versions you install will accumulate in your
~/.rbenv/versionsdirectory.To remove old Ruby versions, simply
rm -rfthe directory of the version you want to remove. You can find the directory of a particular Ruby version with therbenv prefixcommand, e.g.rbenv prefix 1.8.7-p357.The ruby-build plugin provides an
rbenv uninstallcommand to automate the removal process.The simplicity of rbenv makes it easy to temporarily disable it, or uninstall from the system.
- To disable rbenv managing your Ruby versions, simply remove the
rbenv initline from your shell startup configuration. This will remove rbenv shims directory from PATH, and future invocations likerubywill execute the system Ruby version, as before rbenv.
rbenvwill still be accessible on the command line, but your Ruby apps won't be affected by version switching.-
To completely uninstall rbenv, perform step (1) and then remove its root directory. This will delete all Ruby versions that were installed under
`rbenv root`/versions/directory:rm -rf `rbenv root`If you've installed rbenv using a package manager, as a final step perform the rbenv package removal. For instance, for Homebrew:
brew uninstall rbenv
Like
git, therbenvcommand 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-versionfile in the current directory. This version overrides the global version, and can be overridden itself by setting theRBENV_VERSIONenvironment variable or with therbenv shellcommand.$ rbenv local 1.9.3-p327When run without a version number,
rbenv localreports the currently configured local version. You can also unset the local version:$ rbenv local --unsetSets the global version of Ruby to be used in all shells by writing the version name to the
~/.rbenv/versionfile. This version can be overridden by an application-specific.ruby-versionfile, or by setting theRBENV_VERSIONenvironment variable.$ rbenv global 1.8.7-p352The special version name
systemtells rbenv to use the system Ruby (detected by searching your$PATH).When run without a version number,
rbenv globalreports the currently configured global version.Sets a shell-specific Ruby version by setting the
RBENV_VERSIONenvironment variable in your shell. This version overrides application-specific versions and the global version.$ rbenv shell jruby-1.7.1When run without a version number,
rbenv shellreports the current value ofRBENV_VERSION. You can also unset the shell version:$ rbenv shell --unsetNote 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_VERSIONvariable yourself:$ export RBENV_VERSION=jruby-1.7.1Lists 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-1.8.7-2011.03Displays the currently active Ruby version, along with information on how it was set.
$ rbenv version 1.9.3-p327 (set by /Users/sam/.rbenv/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 rehashDisplays 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/irbLists all Ruby versions with the given command installed.
$ rbenv whence rackup 1.9.3-p327 jruby-1.7.1 ree-1.8.7-2011.03You can affect how rbenv operates with the following settings:
name default description RBENV_VERSIONSpecifies the Ruby version to be used.
Also seerbenv shellRBENV_ROOT~/.rbenvDefines the directory under which Ruby versions and shims reside.
Also seerbenv rootRBENV_DEBUGOutputs debug information.
Also as:rbenv --debug <subcommand>RBENV_HOOK_PATHsee wiki Colon-separated list of paths searched for rbenv hooks. RBENV_DIR$PWDDirectory to start searching for .ruby-versionfiles.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>.batsPlease feel free to submit pull requests and file bugs on the issue tracker.