ruby script with flag

[Jillian Kozyra]

Hi,

I am trying to write a ruby script which accepts a flag. That is, I
would like to execute the script by doing:
/assignment2.rb --verbose OR
/assignment2.rb

How would I got about making the script accept a flag?

Thanks,
Jillian

 

[Robert Klemme]

I am trying to write a ruby script which accepts a flag. That is, I
would like to execute the script by doing:
./assignment2.rb --verbose OR
./assignment2.rb

How would I got about making the script accept a flag?

You would use one of the option parsing libraries around. The
standard lib comes with OptionParser and GetoptLong. There are also
other libraries and gems around that do option processing (and
sometimes more). With OptionParser you could do

require 'optparse'

$verbose = false

OptionParser.new do |opts|
# simple
opts.on '-v', '--verbose', 'Print verbose messages' do
$verbose = true
end

# alternative: with negation
opts.on '-v', '--[no-]verbose', 'Print verbose messages' do |flag|
$verbose = flag
end
end.parse! ARGV

puts "verbose is on" if $verbose

Note that OptionParser also gives you some default options, for
example "-h" and "--help".

Kind regards

robert