Separates Ruby PTY spawn stderr from stdout

pty_spawn_stderr_stdout.rb

require "pty"

stderr_reader, stderr_writer = IO.pipe

args = ["-c", "read a; echo was: $a; echo err:$a >&2"]
stdout,stdin,pid = PTY.spawn("/bin/bash", *args, err: stderr_writer.fileno)
stderr_writer.close

stdin.puts "hello"

puts stdout.read
puts stderr_reader.read

Thx for stderr! https://gist.github.com/pre/67c04d0a64abc1929c9ef9ffd3c4469c