Tutorial¶ ↑

Why OptionParser?¶ ↑

When a Ruby program executes, it captures its command-line arguments and options into variable ARGV. This simple program just prints its ARGV:

p ARGV

Execution, with arguments and options:

$ ruby argv.rb foo --bar --baz bat bam
["foo", "--bar", "--baz", "bat", "bam"]

The executing program is responsible for parsing and handling the command-line options.

OptionParser offers methods for parsing and handling those options.

With OptionParser, you can define options so that for each option:

• The code that defines the option and code that handles that option are in the same place.

• The option may take no argument, a required argument, or an optional argument.

• The argument may be automatically converted to a specified class.

• The argument may be restricted to specified forms.

• The argument may be restricted to specified values.

The class also has method help, which displays automatically-generated help text.

Contents¶ ↑

• To Begin With

• Defining Options

• Option Names

  • Short Option Names

  • Long Option Names

  • Mixing Option Names

  • Option Name Abbreviations

• Option Arguments

  • Option with No Argument

  • Option with Required Argument

  • Option with Optional Argument

  • Argument Abbreviations

• Argument Values

  • Explicit Argument Values

    • Explicit Values in Array

    • Explicit Values in Hash

  • Argument Value Patterns

• Keyword Argument into

  • Collecting Options

  • Checking for Missing Options

  • Default Values for Options

• Argument Converters

• Help

• Top List and Base List

• Methods for Defining Options

• Parsing

  • Method parse!

  • Method parse

  • Method order!

  • Method order

  • Method permute!

  • Method permute

To Begin With¶ ↑

To use OptionParser:

1. Require the OptionParser code.

2. Create an OptionParser object.