Working with file in Ruby

file.rb

# Reading whole file
bootstrap = File.read('config/bootstrap')

# Relative path. 
# web_app/
#   app.rb
#   db/sample.db
# In the app.rb
"#{File.expand_path(File.dirname(__FILE__))}/db/sample.db"

# Directory listing
Dir[File.join(File.dirname(__FILE__), "../lib/collector/handlers/*.rb")].each do |file|
  require File.join("collector/handlers", File.basename(file, File.extname(file)))
end