我推荐rbenv* https://github.com/rbenv/rbenv

*如果这符合你的标准:https://github.com/rbenv/rbenv/wiki/Why-rbenv?:

rbenv does… Provide support for specifying application-specific Ruby versions. Let you change the global Ruby version on a per-user basis. 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 or require prompt hacks. 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.

安装

安装Homebrew http://brew.sh

然后:

$ brew update
$ brew install rbenv ruby-build

# Add rbenv to bash so that it loads every time you open a terminal
echo 'if which rbenv > /dev/null; then eval "$(rbenv init -)"; fi' >> ~/.bash_profile
source ~/.bash_profile

$ rbenv install --list
Available versions:
 1.8.5-p113
 1.8.5-p114
 […]
 2.3.1
 2.4.0-dev
 jruby-1.5.6
 […]
$ rbenv install 2.3.1
[…]

设置全局版本:

$ rbenv global 2.3.1
$ ruby -v
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15]

如果您没有显示更新的版本，那么

$ rbenv rehash

通过在存储库根目录中添加.ruby-version来设置存储库的本地版本:

$ cd ~/whatevs/projects/new_repo
$ echo "2.3.1" > .ruby-version

对于OS X，请访问此链接。

sudo gem update --system

然后重启电脑

在终端:rvm gemset使用全局

如果你在Mac上，使用rvm来安装特定版本的Ruby。参见如何在MacOS Mojave上使用Ruby版本管理器(RVM)安装Ruby

确保你遵循了所有的步骤。这对我很管用。

您可以通过查看下载Ruby指定Ruby的最新版本。

获取最新版本: curl -sSL https://get.rvm.io | bash -s stable——ruby 安装: RVM安装2.2 使用它作为默认值: RVM使用2.2——default

或者运行ruby的最新命令:

rvm install ruby --latest
rvm use 2.2 --default

打开终端:

sudo gem update --system 

它的工作原理!