warning: already initialized constant ruby

I have few modules named "Source" and in all modules i have same constants and i keep getting this warning message.below is how i fix this

Module Source
  Source.constants.each do |c|
         remove_const(c.to_sym)
  end  
  #########################
  declare all your constants here
  #########################
end

Faster CSV open and read

FCSV.open('test.csv') do |csv|
     csv.each do |row|
       puts row.first
       break if csv.lineno >= 10
     end
   end

http://www.ruby-forum.com/topic/160439

Working with Files in Ruby

http://www.techotopia.com/index.php/Working_with_Files_in_Ruby

Read input from console in Ruby

puts "Enter A"
a = gets.chomp
puts "Enter B"
b = gets.chomp
c = Integer(a) + Integer(b)
puts c

you can also pass the parameters through the command line. Command line arguments are stores in the array ARGV. so ARGV[0] is the first number and ARGV[1] the second number
#!/usr/bin/ruby

first_number = ARGV[0].to_i
second_number = ARGV[1].to_i

puts first_number + second_number
and you call it like this
% ./plus.rb 5 6
==> 11

Setting up Resque

http://atevans.com/setting-up-resque

Http delete with authentication ruby

require 'rubygems'
require "net/http"

Net::HTTP.start('www.example.com') {|http|                  
            req = Net::HTTP::Delete.new("/api/products/#{product_id}")            
            req.basic_auth '#{user_name}', '#{password}'        
            response = http.request(req)
}

Install sendmail

I used:

Code:

sudo apt-get install sendmail

It installed sendmail and by this command I could test it:

Code:

sudo ps aux | grep sendmail

Result:

Quote:

sudo ps aux | grep sendmail root 10366 0.0 0.7 8216 2020 ? Ss 09:50 0:00 sendmail: MTA: accepting connections 1000 10376 0.0 0.3 2880 796 pts/0 S+ 09:56 0:00 grep sendmail