# 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 `$PATH`. * **Override shell commands like `cd`.** That's dangerous and error-prone. * **Have a configuration file.** There's nothing to configure except which version of Ruby you want to use. * **Install Ruby.** You can build and install Ruby yourself, or use [ruby-build](https://github.com/sstephenson/ruby-build) to automate the process. * **Manage gemsets.** [Bundler](http://gembundler.com/) is a better way to manage application dependencies. If you have projects that are not yet using Bundler you can install the [rbenv-gemset](https://github.com/jamis/rbenv-gemset) plugin. * **Require changes to Ruby libraries for compatibility.** The simplicity of rbenv means as long as it's in your `$PATH`, [nothing](https://rvm.beginrescueend.com/integration/bundler/) [else](https://rvm.beginrescueend.com/integration/capistrano/) 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 ## 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`. ## 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. ### 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. 1. Check out rbenv into `~/.rbenv`. $ cd $ git clone git://github.com/sstephenson/rbenv.git .rbenv 2. Add `~/.rbenv/bin` to your `$PATH` for access to the `rbenv` command-line utility. $ echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> .bash_profile **ZSH note**: Modifiy your `~/.zshrc` file instead of `~/.bash_profile`. 3. Add rbenv init to your shell to enable shims and autocompletion. $ echo 'eval "$(rbenv init -)"' >> .bash_profile 4. Restart your shell so the path changes take effect. You can now begin using rbenv. $ exec $SHELL 5. 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](https://github.com/sstephenson/ruby-build) provides an `rbenv install` command that simplifies the process of installing new Ruby versions to: $ rbenv install 1.9.2-p290 6. 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 ### Upgrading an existing installation ### 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 ### Homebrew on Mac OS X ### You can also install rbenv using the [Homebrew](http://mxcl.github.com/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 "$(rbenv init -)"` to your profile as stated in the caveats. You'll only ever have to do this once. ### Neckbeard Configuration ### Skip this section unless you must know what every line in your shell profile is doing. `rbenv init` is the only command that crosses the line of loading extra commands into your shell. Coming from rvm, some of you might be opposed to this idea. Heres what `rbenv init` actually does: 1. Sets up your shims path. This is the only requirement for rbenv to functional properly. You can do this by hand by prepending `~/.rbenv/shims` to your `$PATH`. 2. 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. 3. Initial rehash. From time to time you'll need to rebuild you're shim files. Doing this on init makes sure everything is up to date. `rbenv rehash` can always be ran manually. 4. Install sh dispatcher. This bit is also optional but allows rbenv and plugins to change variables in your current shell. This makes commands like `rbenv shell` possible. This doesn't do anything crazy like override `cd` or hack your shell prompt. But for some reason you may need `rbenv` to be a real script rather than a shell function. Run `rbenv init -` for yourself to see exactly whats its doing. ## Usage ## Like `git`, the `rbenv` command delegates to subcommands based on its first argument. The most common subcommands are: ### 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. ### 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 ### 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 ### 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 ### 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) ### 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 ### 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 ### 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 ## Development ## The rbenv source code is [hosted on GitHub](https://github.com/sstephenson/rbenv). 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](https://github.com/sstephenson/rbenv/issues). ### Version History ### **HEAD** * Renamed `rbenv set-default` to `rbenv global` and `rbenv set-local` to `rbenv local`. The `set-` 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 `$RBENV_DEBUG` environment variable is set. * Refactored the autocompletion system so that completions are now built-in to each command and shared between bash and zsh. * Added support for plugin bundles in `~/.rbenv/plugins` as documented in [issue #102](https://github.com/sstephenson/rbenv/pull/102). * Added `/usr/local/etc/rbenv.d` to the list of directories searched for rbenv hooks. * Added support for an `$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 run `rbenv 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 of `set -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. ### 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.