это наш химический дом для печальных жителей Земли

task :greet do
	puts 'Hello world!'
end

$ rake greet
(in /home/myusername/rails3/rails_app)
Hello world!

task :greet do
	puts 'Hello world!'
end
task :ask => :greet do
	puts 'How are u?!'
end

$ rake ask
(in /home/myusername/rails3/rails_app)
Hello world!
How are u?!

task :first_nah do
	product=Product.first
	puts product.title
end

$ rake first_nah
(in  /home/myusername/rails3/rails_app)
rake aborted!
uninitialized constant Product

task :nah_first => :environment do
	product=Product.first
	puts product.title
end

task :nah_first => :environment do
	product=Product.first
	puts product.title
end
 
task :nah_last => :environment do
	product=Product.last
	puts product.title
end

namespace :nah do
	task :first => :environment do
		product=Product.first
		puts product.title
	end
	task :last => :environment do
		product=Product.last
		puts product.title
	end
end

$ rake nah:last
(in /home/myusername/rails3/rails_app)
Last_product
$ rake nah:first
(in /home/myusername/rails3/rails_app)
First_product

namespace :nah do
        #код заданий :first и :last
	task :all => [:first,:last]
end

$ rake nah:all
(in /home/myusername/rails3/rails_app)
First_product
Last_product

namespace :shop do
	task :product => :environment do
		product=Product.where('id > ?',20).first
		puts product.title
	end
 
	task :categor => :environment do
		cat=Categor.where('id > ?',20).first
		puts cat.title
	end
	task :all => [:product,:categor]
end

namespace :shop do
	task :product => :environment do 
		puts echo(Product).title
	end
 
	task :categor => :environment do 
		puts echo(Categor).title
	end
	task :all => [:product,:categor]
 
	def echo (model_class)
		model_class.where('id > ?',20).first
	end
end

namespace :shop do
	desc 'Show first product, which id > 20'
	task :product => :environment do
		puts echo(Product).title
	end
 
	desc 'Show first categor, which id > 20'
	task :categor => :environment do
		puts echo(Categor).title
	end
 
        desc 'Show first product and category'
	task :all => [:product,:categor]
 
	def echo (model_class)
		model_class.where('id > ?',20).first
	end
end

$ rake -T
(in /home/myusername/rails3/rails_app)
rake about              # List versions of all Rails...
...
rake shop:all           # Show first product and categor
rake shop:categor       # Show first categor, which id > 20
rake shop:product       # Show first product, which id > 20