decode64

Returns the Base64-decoded version of str.

  require 'base64'
  str = 'VGhpcyBpcyBsaW5lIG9uZQpUaGlzIG' +
        'lzIGxpbmUgdHdvClRoaXMgaXMgbGlu' +
        'ZSB0aHJlZQpBbmQgc28gb24uLi4K'
  puts Base64.decode64(str)

Generates:

   This is line one
   This is line two
   This is line three
   And so on...