Class: Gem::Commands::HelpCommand

Relationships & Source Files
Super Chains via Extension / Inclusion / Inheritance
Class Chain: self, `::Gem::Command`
Instance Chain: self, `::Gem::Command`, `::Gem::UserInteraction`, `::Gem::DefaultUserInteraction`, `::Gem::Text`
Inherits:	Gem::Command Object Gem::Command Gem::Commands::HelpCommand
Defined in:	lib/rubygems/commands/help_command.rb

Constant Summary

EXAMPLES = Internal use only
# File 'lib/rubygems/commands/help_command.rb', line 7

<<-EOF
Some examples of 'gem' usage.

* Install 'rake', either from local directory or remote server:

  gem install rake

* Install 'rake', only from remote server:

  gem install rake --remote

* Install 'rake', but only version 0.3.1, even if dependencies
are not met, and into a user-specific directory:

  gem install rake --version 0.3.1 --force --user-install

* List local gems whose name begins with 'D':

  gem list D

* List local and remote gems whose name contains 'log':

  gem search log --both

* List only remote gems whose name contains 'log':

  gem search log --remote

* Uninstall 'rake':

  gem uninstall rake

* Create a gem:

  See https://guides.rubygems.org/make-your-own-gem/

* See information about RubyGems:

  gem environment

* Update all gems on your system:

  gem update

* Update your local version of RubyGems

  gem update --system
EOF

GEM_DEPENDENCIES = Internal use only
# File 'lib/rubygems/commands/help_command.rb', line 56

<<-EOF
A gem dependencies file allows installation of a consistent set of gems across
multiple environments.  The RubyGems implementation is designed to be
compatible with Bundler's Gemfile format.  You can see additional
documentation on the format at:

https://bundler.io

RubyGems automatically looks for these gem dependencies files:

* gem.deps.rb
* Gemfile
* Isolate

These files are looked up automatically using `gem install -g`, or you can
specify a custom file.

When the RUBYGEMS_GEMDEPS environment variable is set to a gem dependencies
file the gems from that file will be activated at startup time.  Set it to a
specific filename or to "-" to have RubyGems automatically discover the gem
dependencies file by walking up from the current directory.

You can also activate gem dependencies at program startup using
Gem.use_gemdeps.

NOTE: Enabling automatic discovery on multiuser systems can lead to execution
of arbitrary code when used from directories outside your control.

Gem Dependencies
================

Use #gem to declare which gems you directly depend upon:

gem 'rake'

To depend on a specific set of versions:

gem 'rake', '~> 10.3', '>= 10.3.2'

RubyGems will require the gem name when activating the gem using
the RUBYGEMS_GEMDEPS environment variable or Gem::use_gemdeps.  Use the
require: option to override this behavior if the gem does not have a file of
that name or you don't want to require those files:

gem 'my_gem', require: 'other_file'

To prevent RubyGems from requiring any files use:

gem 'my_gem', require: false

To load dependencies from a .gemspec file:

gemspec

RubyGems looks for the first .gemspec file in the current directory.  To
override this use the name: option:

gemspec name: 'specific_gem'

To look in a different directory use the path: option:

gemspec name: 'specific_gem', path: 'gemspecs'

To depend on a gem unpacked into a local directory:

gem 'modified_gem', path: 'vendor/modified_gem'

To depend on a gem from git:

gem 'private_gem', git: 'git@my.company.example:private_gem.git'

To depend on a gem from github:

gem 'private_gem', github: 'my_company/private_gem'

To depend on a gem from a github gist:

gem 'bang', gist: '1232884'

Git, github and gist support the ref:, branch: and tag: options to specify a
commit reference or hash, branch or tag respectively to use for the gem.

Setting the submodules: option to true for git, github and gist dependencies
causes fetching of submodules when fetching the repository.

You can depend on multiple gems from a single repository with the git method:

git 'https://github.com/rails/rails.git' do
  gem 'activesupport'
  gem 'activerecord'
end

Gem Sources
===========

RubyGems uses the default sources for regular `gem install` for gem
dependencies files.  Unlike bundler, you do need to specify a source.

You can override the sources used for downloading gems with:

source 'https://gem_server.example'

You may specify multiple sources.  Unlike bundler the prepend: option is not
supported. Sources are used in-order, to prepend a source place it at the
front of the list.

Gem Platform
============

You can restrict gem dependencies to specific platforms with the #platform
and #platforms methods:

platform :ruby_21 do
  gem 'debugger'
end

See the bundler Gemfile manual page for a list of platforms supported in a gem
dependencies file.:

https://bundler.io/v2.5/man/gemfile.5.html

Ruby Version and Engine Dependency
==================================

You can specify the version, engine and engine version of ruby to use with
your gem dependencies file.  If you are not running the specified version
RubyGems will raise an exception.

To depend on a specific version of ruby:

ruby '2.1.2'

To depend on a specific ruby engine:

ruby '1.9.3', engine: 'jruby'

To depend on a specific ruby engine version:

ruby '1.9.3', engine: 'jruby', engine_version: '1.7.11'

Grouping Dependencies
=====================

Gem dependencies may be placed in groups that can be excluded from install.
Dependencies required for development or testing of your code may be excluded
when installed in a production environment.

A #gem dependency may be placed in a group using the group: option:

gem 'minitest', group: :test

To install dependencies from a gemfile without specific groups use the
`--without` option for `gem install -g`:

$ gem install -g --without test

The group: option also accepts multiple groups if the gem fits in multiple
categories.

Multiple groups may be excluded during install by comma-separating the groups for `--without` or by specifying `--without` multiple times.

The #group method can also be used to place gems in groups:

group :test do
  gem 'minitest'
  gem 'minitest-emoji'
end

The #group method allows multiple groups.

The #gemspec development dependencies are placed in the :development group by
default.  This may be overridden with the :development_group option:

gemspec development_group: :other

EOF

PLATFORMS = Internal use only
# File 'lib/rubygems/commands/help_command.rb', line 233

<<-'EOF'
RubyGems platforms are composed of three parts, a CPU, an OS, and a
version.  These values are taken from values in rbconfig.rb.  You can view
your current platform by running `gem environment`.

RubyGems matches platforms as follows:

* The CPU must match exactly unless one of the platforms has
  "universal" as the CPU or the local CPU starts with "arm" and the gem's
  CPU is exactly "arm" (for gems that support generic ARM architecture).
* The OS must match exactly.
* The versions must match exactly unless one of the versions is nil.

For commands that install, uninstall and list gems, you can override what
RubyGems thinks your platform is with the --platform option.  The platform
you pass must match "#{cpu}-#{os}" or "#{cpu}-#{os}-#{version}".  On mswin
platforms, the version is the compiler version, not the OS version.  (Ruby
compiled with VC6 uses "60" as the compiler version, VC8 uses "80".)

For the ARM architecture, gems with a platform of "arm-linux" should run on a
reasonable set of ARM CPUs and not depend on instructions present on a limited
subset of the architecture.  For example, the binary should run on platforms
armv5, armv6hf, armv6l, armv7, etc.  If you use the "arm-linux" platform
please test your gem on a variety of ARM hardware before release to ensure it
functions correctly.

Example platforms:

x86-freebsd        # Any FreeBSD version on an x86 CPU
universal-darwin-8 # Darwin 8 only gems that run on any CPU
x86-mswin32-80     # Windows gems compiled with VC8
armv7-linux        # Gem complied for an ARMv7 CPU running linux
arm-linux          # Gem compiled for any ARM CPU running linux

When building platform gems, set the platform in the gem specification to
Gem::Platform::CURRENT.  This will correctly mark the gem with your ruby's
platform.
EOF

SUBCOMMANDS = Internal use only

NOTE: when updating also update Gem::Command::HELP

# File 'lib/rubygems/commands/help_command.rb', line 274

[
  ["commands",         :show_commands],
  ["options",          Gem::Command::HELP],
  ["examples",         EXAMPLES],
  ["gem_dependencies", GEM_DEPENDENCIES],
  ["platforms",        PLATFORMS],
].freeze

`::Gem::Command` - Inherited

HELP

Class Attribute Summary

`::Gem::Command` - Inherited

.build_args	Arguments used when building gems.
.build_args=, .extra_args, .extra_args=

Class Method Summary

.new ⇒ HelpCommand constructor

`::Gem::Command` - Inherited

.add_common_option,
.add_specific_extra_args	Add a list of extra arguments for the given command.
.common_options,
.new	Initializes a generic gem command named `command`.
.specific_extra_args	Return an array of extra arguments for the command.
.specific_extra_args_hash	Accessor for the specific extra args hash (self initializing).

Instance Attribute Summary

`::Gem::Command` - Inherited

#command	The name of the command.
#defaults	The default options for the command.
#deprecated?,
#options	The options for the command.
#program_name	The name of the command for command-line invocation.
#summary	A short description of the command.

`::Gem::DefaultUserInteraction` - Included

#ui	See DefaultUserInteraction.ui
#ui=	See DefaultUserInteraction.ui=

Instance Method Summary

#execute
#show_command_help(command_name) Internal use only
#show_commands Internal use only
#usage Internal use only

`::Gem::Command` - Inherited

#add_extra_args	Adds extra args from ~/.gemrc.
#add_option	Add a command-line option and handler to the command.
#arguments	Override to provide details of the arguments a command takes.
#begins?	True if `long` begins with the characters from `short`.
#check_deprecated_options,
#defaults_str	Override to display the default values of the command options.
#deprecate_option	Mark a command-line option as deprecated, and optionally specify a deprecation horizon.
#description	Override to display a longer description of what this command does.
#execute	Override to provide command handling.
#get_all_gem_names	Get all gem names from the command line.
#get_all_gem_names_and_versions	Get all [gem, version] from the command line.
#get_one_gem_name	Get a single gem name from the command line.
#get_one_optional_argument	Get a single optional argument from the command line.
#handle_options	Handle the given list of arguments by parsing them and recording the results.
#handles?	True if the command handles the given argument list.
#invoke	Invoke the command with the given list of arguments.
#invoke_with_build_args	Invoke the command with the given list of normal arguments and additional build arguments.
#merge_options	Merge a set of command options with the set of default options (without modifying the default option hash).
#remove_option	Remove previously defined command-line argument `name`.
#show_help	Display the help message for the command.
#show_lookup_failure	Display to the user that a gem couldn’t be found and reasons why –.
#usage	Override to display the usage for an individual gem command.
#when_invoked	Call the given block when invoked.
#add_parser_run_info	Adds a section with `title` and `content` to the parser help view.
#configure_options,
#create_option_parser	Creates an option parser and fills it in with the help info for the command.
#option_is_deprecated?,
#parser	Create on demand parser.
#wrap	Wraps `text` to `width`
#extract_gem_name_and_version, #add_parser_description, #add_parser_options, #add_parser_summary

`::Gem::UserInteraction` - Included

#alert	Displays an alert `statement`.
#alert_error	Displays an error `statement` to the error output location.
#alert_warning	Displays a warning `statement` to the warning output location.
#ask	Asks a `question` and returns the answer.
#ask_for_password	Asks for a password with a `prompt`
#ask_yes_no	Asks a yes or no `question`.
#choose_from_list	Asks the user to answer `question` with an answer from the given `list`.
#say	Displays the given `statement` on the standard output (or equivalent).
#terminate_interaction	Terminates the RubyGems process with the given `exit_code`
#verbose	Calls `say` with `msg` or the results of the block if really_verbose is true.

`::Gem::DefaultUserInteraction` - Included

#use_ui

See DefaultUserInteraction.use_ui

`::Gem::Text` - Included

#clean_text	Remove any non-printable characters and make the text suitable for printing.
#format_text	Wraps `text` to `wrap` characters and optionally indents by `indent` characters.
#levenshtein_distance	Returns a value representing the “cost” of transforming str1 into str2 Vendored version of `DidYouMean::Levenshtein.distance` from the ruby/did_you_mean gem @ 1.4.0 github.com/ruby/did_you_mean/blob/2ddf39b874808685965dbc47d344cf6c7651807c/lib/did_you_mean/levenshtein.rb#L7-L37.
#truncate_text, #min3

Constructor Details

.new ⇒ `HelpCommand`

[ GitHub ]

# File 'lib/rubygems/commands/help_command.rb', line 283


def initialize
  super "help", "Provide help on the 'gem' command"

  @command_manager = Gem::CommandManager.instance
end

Instance Method Details

#execute

[ GitHub ]

# File 'lib/rubygems/commands/help_command.rb', line 293


def execute
  arg = options[:args][0]

  _, help = SUBCOMMANDS.find do |command,|
    begins? command, arg
  end

  if help
    if Symbol === help
      send help
    else
      say help
    end
    return
  end

  if options[:help]
    show_help

  elsif arg
    show_command_help arg

  else
    say Gem::Command::HELP
  end
end

#show_command_help(command_name)

This method is for internal use only.

[ GitHub ]

# File 'lib/rubygems/commands/help_command.rb', line 361


def show_command_help(command_name) # :nodoc:
  command_name = command_name.downcase

  possibilities = @command_manager.find_command_possibilities command_name

  if possibilities.size == 1
    command = @command_manager[possibilities.first]
    command.invoke("--help")
  elsif possibilities.size > 1
    alert_warning "Ambiguous command #{command_name} (#{possibilities.join(", ")})"
  else
    alert_warning "Unknown command #{command_name}. Try: gem help commands"
  end
end

#show_commands

This method is for internal use only.

[ GitHub ]

# File 'lib/rubygems/commands/help_command.rb', line 320


def show_commands # :nodoc:
  out = []
  out << "GEM commands are:"
  out << nil

  margin_width = 4

  desc_width = @command_manager.command_names.map(&:size).max + 4

  summary_width = 80 - margin_width - desc_width
  wrap_indent = " " * (margin_width + desc_width)
  format = "#{" " * margin_width}%-#{desc_width}s%s"

  @command_manager.command_names.each do |cmd_name|
    command = @command_manager[cmd_name]

    next if command&.deprecated?

    summary =
      if command
        command.summary
      else
        "[No command found for #{cmd_name}]"
      end

    summary = wrap(summary, summary_width).split "\n"
    out << format(format, cmd_name, summary.shift)
    until summary.empty? do
      out << "#{wrap_indent}#{summary.shift}"
    end
  end

  out << nil
  out << "For help on a particular command, use 'gem help COMMAND'."
  out << nil
  out << "Commands may be abbreviated, so long as they are unambiguous."
  out << "e.g. 'gem i rake' is short for 'gem install rake'."

  say out.join("\n")
end

#usage

This method is for internal use only.

[ GitHub ]

# File 'lib/rubygems/commands/help_command.rb', line 289


def usage # :nodoc:
  "#{program_name} ARGUMENT"
end

Class: Gem::Commands::HelpCommand

Constant Summary

::Gem::Command - Inherited

Class Attribute Summary

::Gem::Command - Inherited

Class Method Summary

::Gem::Command - Inherited

Instance Attribute Summary

::Gem::Command - Inherited

::Gem::DefaultUserInteraction - Included

Instance Method Summary

::Gem::Command - Inherited

::Gem::UserInteraction - Included

::Gem::DefaultUserInteraction - Included

::Gem::Text - Included

Constructor Details

.new ⇒ HelpCommand

Instance Method Details

#execute

#show_command_help(command_name)

#show_commands

#usage

`::Gem::Command` - Inherited

`::Gem::Command` - Inherited

`::Gem::Command` - Inherited

`::Gem::Command` - Inherited

`::Gem::DefaultUserInteraction` - Included

`::Gem::Command` - Inherited

`::Gem::UserInteraction` - Included

`::Gem::DefaultUserInteraction` - Included

`::Gem::Text` - Included

.new ⇒ `HelpCommand`