Using tempfile

gistfile1.rb

# Use open to ensure tempfile is cleaned up asap
Tempfile.open("somename") do |tfile|
  # Stage 1 - create the tempfile with some data
  tfile.write "some bytes"
  tfile.close

  # Stage 2 - use the tempfile
  File.open(tfile.path) do |file|
    assert "some bytes", file.read
  end
end

Also a good example but in my case I need to pass the file path to another API so unlink is not possible.

Ah, BEWARE: Tempfile.open just delegates to File.open so you don't actually get a tempfile with a randomly generated name. Ruby 2.1 has a nice Tempfile.create method but 2.0 doesn't support anything beyond Tempfile.new.