How do I temporarily redirect stderr in Ruby?

Question

I\'d like to temporarily redirect stderr in a Ruby script for the duration of a block, ensuring that I reset it to its original value at the end of the block.

I had

Answer 1

Essentially the same as @molf's answer, and has the same usage:

require "stringio"
def capture_stderr
  real_stderr, $stderr = $stderr, StringIO.new
  yield
  $stderr.string
ensure
  $stderr = real_stderr
end

It uses StringIO very slightly more concisely, and preserves $stderr as whatever it was before capture_stderr was called.