1.　ヘルプ

2.　コマンドについてのヘルプ

1.　ヘルプ

　何しろヘルプの出し方もわからない。


> 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 gem_dependencies    gem dependencies file guide
    gem help platforms           gem platforms guide
    gem help <COMMAND>           show help on COMMAND
                                   (e.g. 'gem help install')
    gem server                   present a web page at
                                 http://localhost:8808/
                                 with info about installed gems
  Further information:
    http://guides.rubygems.org


2.　コマンドについてのヘルプ

　なるほど


gem help コマンド


　で、コマンドに関するヘルプが出力されるわけだ。
　search について見るとこうなっていました。


> gem help search
Usage: gem search [REGEXP] [options]

  Options:
    -i, --[no-]installed             Check for installed gem
    -I                               Equivalent to --no-installed
    -v, --version VERSION            Specify version of gem to search
                                     for use with --installed
    -d, --[no-]details               Display detailed information of gem(s)
        --[no-]versions              Display only gem names
    -a, --all                        Display all gem versions
    -e, --exact                      Name of gem(s) to query on matches the
                                     provided STRING
        --[no-]prerelease            Display prerelease versions


  Deprecated Options:
    -u, --[no-]update-sources        Update local source cache


  Local/Remote Options:
    -l, --local                      Restrict operations to the LOCAL domain
    -r, --remote                     Restrict operations to the REMOTE domain
    -b, --both                       Allow LOCAL and REMOTE operations
    -B, --bulk-threshold COUNT       Threshold for switching to bulk
                                     synchronization (default 1000)
        --clear-sources              Clear the gem sources
    -s, --source URL                 Append URL to list of remote gem sources
    -p, --[no-]http-proxy [URL]      Use HTTP proxy for remote operations


  Common Options:
    -h, --help                       Get help on this command
    -V, --[no-]verbose               Set the verbose level of output
    -q, --quiet                      Silence command progress meter
        --silent                     Silence RubyGems output
        --config-file FILE           Use this config file instead of default
        --backtrace                  Show stack backtrace on errors
        --debug                      Turn on Ruby debugging
        --norc                       Avoid loading any .gemrc file


  Arguments:
    REGEXP        regexp to search for in gem name

  Summary:
    Display remote gems whose name matches REGEXP

  Description:
    The search command displays remote gems whose name matches the given
    regexp.

    The --details option displays additional details from the gem but will
    take a little longer to complete as it must download the information
    individually from the index.

    To list local gems use the list command.

  Defaults:
    --remote --no-details


　search する項目に関しては、REGEX と書いてあるので正規表現が使えるわけね。