using ack in place of grep

For Chromium browser versions greater than 34, to use flash one must install Pepper flash.

For Ubuntu 14.04 or newer, run

sudo apt-get install pepperflashplugin-nonfree
sudo update-pepperflashplugin-nonfree --status 
# to see what version of...

The extend method will mix a module’s methods at the class level.

On the other hand, the include method will mix a module’s methods at the instance level, meaning the methods will become instance methods of the class.

module Stringify
  # R...

class Myclass
  def one
    puts "one is called"
  end
end    

ss = Myclass.new

puts Myclass.methods 
# returns array of methods for the class. Includes both class and instance methods and methods inherited from parents.
puts Myclass.instanc...

This is to install adobe flash player in Ubuntu 14.04 or higher. This works for Firefox browser.

If you have a 32-bit OS, run

sudo apt-get update
sudo apt-get install flashplugin-installer

Make sure each of the commands executed success...

In Ruby, send is often introduced as a way to show how everything is an object

1.send(:+, 1)  ## -> 2

It can also be used to call private or protected methods from outside a given class as explained below.

class Myclass
  def method...

To check if a given package is installed in Debian / Ubuntu, type

dpkg -s <package-name>

To get a neater output use dpkg-query which accepts wildcards as well.

dpkg-query -l <package-name>

In Redhat / Fedora / CentOS use the foll...

I've noticed that Incognito mode retain cache from the previous session, it just don't collect any new cache while in incognito.

I usually clear the cache/cookies then go into incognito, or run a different browser profile, or a different browser ...

class Person    
    def initialize(name)
        @name = name
    end    
end

class Employee < Person
end

emp = Employee.new # throws error wrong number of arguments

emp = Employee.new("foo") # parent class initialize method is called

cla...

attr_accessor is used to create setter and getter methods for instance variables so that they can be accessed outside the class. initialize is the special method in ruby that gets called when an object is instantiated.

class Birthday
 attr_ac...

As we have object.class method in Ruby, to check the class of a variable in Javascript, here is the snippet

var ss = "some string";
alert (typeof ss);  #=> string
alert (typeof pp);  #=> undefined