ｇｅｍでパッケージ管理をするため、概要をまとめる。
■現在のバージョン、he;pコマンド
# gem -v
0.9.0

# gem --help

RubyGems is a sophisticated package manager for Ruby.  This is a
basic help message containing pointers to more information.

  Usage:
    gem -h/--help
    gem -v/--version
    gem command [arguments...] [options...]

  Examples:
    gem install rake
    gem list --local
    gem build package.gemspec
    gem help install

  Further help:
    gem help commands            list all 'gem' commands
    gem help examples            show some examples of usage
    gem help <COMMAND>           show help on COMMAND
                                   (e.g. 'gem help install')
  Further information:
    http://rubygems.rubyforge.org

# gem help command

GEM commands are:

    build             Build a gem from a gemspec
    cert              Adjust RubyGems certificate settings
    check             Check installed gems
    cleanup           Cleanup old versions of installed gems in the local repository
    contents          Display the contents of the installed gems
    dependency        Show the dependencies of an installed gem
    environment       Display RubyGems environmental information
    help              Provide help on the 'gem' command
    install           Install a gem into the local repository
    list              Display all gems whose name starts with STRING
    query             Query gem information in local or remote repositories
    rdoc              Generates RDoc for pre-installed gems
    search            Display all gems whose name contains STRING
    specification     Display gem specification (in yaml)
    uninstall         Uninstall a gem from the local repository
    unpack            Unpack an installed gem to the current directory
    update            Update the named gem (or all installed gems) in the local repository

■使用頻度が高いと思われるコマンド