Ruby optparse example

script.rb

require 'bundler/inline'

gemfile do 
  source 'https://rubygems.org'
  gem 'mail',         require: 'mail'
  gem 'json',         require: 'json'
  gem 'optparse',     require: true
  gem 'ostruct',      require: true
end

opt = OpenStruct.new(
  server: nil, user: nil, pass: nil
)

option_parser = OptionParser.new do |opts|
  opts.banner = "A simple email sender"
  opts.separator ""
  opts.separator "Help menu:"

  opts.on("-s", "--server HOST:PORT", "SMTP server and its port.", "\te.g. smtp.office365.com:587") do |o|
    opt.server = o
  end

  opts.on("-u", "--user USER", "Username to authenticate.", "\te.g. [email protected]") do |o|
    opt.user = o
  end

  opts.on("-p", "--pass PASS", "Password to authenticate") do |o|
    opt.pass = o
  end

  opts.on("-h", "--help", "Show this message.") do
    puts logo
    puts opts
    exit!
  end

  opts.on_tail "\nUsage:\n" + "  #{File.basename(__FILE__)} <OPTIONS>"
  opts.on_tail "Example:"
  opts.on_tail %{  $#{File.basename(__FILE__)} -s smtp.office365.com:587 -u [email protected] -p P@ssword1\n\n}
end

begin
  pp option_parser.parse!(ARGV)
  
rescue OptionParser::MissingArgument => e
  puts option_parser
  e.args.each {|arg| puts '[!] '+ "#{e.reason.capitalize} for '#{arg}' option."}
rescue OptionParser::InvalidOption => e
  puts option_parser
  pp e
rescue Exception => e
  puts "#{$PROGRAM_NAME} Exception".error
  puts e.backtrace_locations
  puts e
end