Ruby - Convert File to String

file = File.open("path-to-file.tar.gz")
contents = ""
file.each {|line|
  contents << line
}

newFile = File.open("test.tar.gz", "w")
newFile.write(contents)

file = File.open("path-to-file.tar.gz", "rb")
contents = file.read

s = File.open(filename, 'rb') { |f| f.read }

s = IO.read(filename)

contents = File.open('path-to-file.tar.gz', 'rb') { |f| f.read }

require 'base64'

file_contents = Base64.encode64(tar_file_data)

contents = File.read("e.tgz")
newFile = File.open("ee.tgz", "w")
newFile.write(contents)

string = File.open('file.txt', 'rb') { |file| file.read }