Ruby in a Nutshell

Ruby in Action

Like Python or Perl, Ruby is a scripting language. Scripting languages offer some great advantages over other languages, such as C++ and Java. They allow programmers to show off a lot of programming concepts and principles in a relatively small amount of space. Ruby does this, while maintaining code readability.

# the "Hello World."
print "Hello World.\n"

# output file contents in reverse order
print File::readlines(path).reverse

# print lines that contains the word "Ruby".
while line = gets(  )
  if /Ruby/ =~ line
    print line
  end
end


# class and methods
class Animal
  def legs
    puts 4
  end
end

class Dog<Animal
  def bark
    puts "bow!"
  end
end

fred = Dog::new
fred.legs                # prints 4
fred.bark                # prints bow!

# exception handling
begin
  printf "size of %s is %d\n", path, File::size(path)
rescue
  printf "error! probably %s does not exist\n", path
end

# rename all files to lowercase names
ARGV.each {|path| File::rename(path, path.downcase)}

# network access
require 'socket'
print TCPSocket::open("localhost", "daytime").read

# Ruby/Tk
require 'tk'
TkButton.new(nil, 'text'=>'hello', 'command'=>'exit').pack
Tk.mainloop