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A mixin for creating command line applications - gives an easy DSL for argument specification and processing

README.rdoc

Mixlib::CLI

Mixlib::CLI provides a class-based command line option parsing object, like the one used in Chef, Ohai and Relish. To use in your project:

require 'rubygems'
require 'mixlib/cli'

class MyCLI
  include Mixlib::CLI

  option :config_file, 
    :short => "-c CONFIG",
    :long  => "--config CONFIG",
    :default => 'config.rb',
    :description => "The configuration file to use"

  option :log_level, 
    :short => "-l LEVEL",
    :long  => "--log_level LEVEL",
    :description => "Set the log level (debug, info, warn, error, fatal)",
    :required => true,
    :proc => Proc.new { |l| l.to_sym }

  option :help,
    :short => "-h",
    :long => "--help",
    :description => "Show this message",
    :on => :tail,
    :boolean => true,
    :show_options => true,
    :exit => 0

end

# ARGV = [ '-c', 'foo.rb', '-l', 'debug' ]
cli = MyCLI.new
cli.parse_options
cli.config[:config_file] # 'foo.rb'
cli.config[:log_level]   # :debug

If you are using this in conjunction with Mixlib::Config, you can do something like this (building on the above definition):

class MyConfig
  extend(Mixlib::Config)

  log_level   :info
  config_file "default.rb"
end

class MyCLI
  def run(argv=ARGV)
    parse_options(argv)
    MyConfig.merge!(config)
  end
end

c = MyCLI.new
# ARGV = [ '-l', 'debug' ]
c.run
MyConfig[:log_level] # :debug

Available arguments to 'option':

:short

The short option, just like from optparse. Example: “-l LEVEL”

:long

The long option, just like from optparse. Example: “–level LEVEL”

:description

The description for this item, just like from optparse.

:default

A default value for this option

:required

Prints a message informing the user of the missing requirement, and exits. Default is false.

:on

Set to :tail to appear at the end, or :head to appear at the top.

:boolean

If this option takes no arguments, set this to true.

:show_options

If you want the option list printed when this option is called, set this to true.

:exit

Exit your program with the exit code when this option is specified. Example: 0

:proc

If set, the configuration value will be set to the return value of this proc.

New in 1.2.2

:required works, and we now support Ruby-style boolean option negation (e.g. '–no-cookie' will set 'cookie' to false if the option is boolean)

New in 1.2.0

We no longer destructively manipulate ARGV.

Have fun!

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