• RakeCommander is loaded from the repo branch you are checked out.

The Rakefile Examples.rake has three lines that can serve as a guide. One were we require rake-commander, another where we define our RakeCommander classes, and one where we load them as actual Rake tasks.

require_relative '../lib/rake-commander'
RakeCommander::Patcher.debug = ENV['COMMANDER_DEBUG'] == "true"
Dir["#{__dir__}/*_example.rb"].sort.each {|file| require_relative file }
RakeCommander.self_load

• To see the patches in action, you can add COMMANDER_DEBUG=true to a .env file

rake -T examples

rake examples:basic -- -h
rake examples:basic -- -z -e prod

Two tasks where chainer calls chained through a shell call to rake.

• Read well the example before running it.

rake examples:chainer -- -h
rake examples:chained -- -h

Same as the previous example but these tasks inherit from the previous example, extending their behaviour and changing the options.

rake examples:chainer_plus -- -h
rake examples:chained_plus -- -h

The option --exit-on-error allows the error handler defined in chained_plus to decide if it should raise the error or just do an exit 1

• This is possible because the order that the options have been declared. Observe that they --say option has been removed and redefined after the option --exit-on-error has been defined.
• OptionParser switches are processed in order and, therefore, the error on --say only pops up after the --exit on-error option has been already parsed.

While this will raise the error (with a trace):

$ rake examples:chainer_plus -- --chain --say
Calling --> 'rake examples:chained_plus -- --say'
Parsed results when 'missing argument' error was raised
on option '--say SOMETHING' => {}
rake aborted!
RakeCommander::Options::Error::MissingArgument: (examples:chained_plus) missing required argument in option: --say SOMETHING (-s)
< here back trace>
Tasks: TOP => examples:chained_plus
(See full trace by running task with --trace)
* Failed to running 'rake examples:chained_plus -- --say'

This will only print the error with an exit 1:

$  rake examples:chainer_plus -- --chain --say --exit-on-error
Calling --> 'rake examples:chained_plus -- --exit-on-error --say'
Parsed results when 'missing argument' error was raised
on option '--say SOMETHING' => {:e=>true}
(examples:chained_plus) missing required argument in option: --say SOMETHING (-s)
* Failed to running 'rake examples:chained_plus -- --exit-on-error --say'