RubyGems是一个方便而强大的Ruby程序包管理器（ package manager），类似RedHat的RPM.它将一个Ruby应用程序打包到一个gem里，作为一个安装单元。 特点： 能远程安装包 包之间依赖关系的管理 简单可靠的卸载（uninstallation） 查询机制，能查询本地和远程服务器的包信息 能保持一个包的不同版本 基于Web的查看接口，能查看你安装的gem的信息。
1.3.3 版本引入一些新的特性以及修复了一些bug，详情如下：
新特性:
* `gem server` allows port names (from /etc/services) with --port.
* `gem server` now has search that jumps to RDoc. Patch #22959 by Vladimir Dobriakov.
* `gem spec` can retrieve single fields from a spec (like `gem spec rake authors`).
* Gem::Specification#has_rdoc= is deprecated and ignored (defaults to true)
* RDoc is now generated regardless of Gem::Specification#has_rdoc?
修复的bug:
* `gem clean` now cleans up --user-install gems. Bug #25516 by Brett Eisenberg.
* Gem.bin_path now escapes paths with spaces.
* Rake extension builder uses explicit correctly loads rubygems when invoking rake.
* Prerelease versions now match "~>" correctly. Patch #25759 by Yossef Mendelssohn.
* Check bindir for executables, not root when validating. Bug reported by David Chelimsky.
* Remove Time.today, no way to override it before RubyGems loads. Bug #25564 by Emanuele Vicentini
* Raise Gem::Exception for #installation_path when not installed. Bug #25741 by Daniel Berger.
* Don't raise in Gem::Specification#validate when homepage is nil. Bug #25677 by Mike Burrows.
* Uninstall executables from the correct directory. Bug #25555 by Brett Eisenberg.
* Raise Gem::LoadError if Kernel#gem fails due to previously-loaded gem. Bug reported by Alf Mikula.
