Question

I am running the following (backup) code in a Ruby script:

 for directory in directories
   print `s3sync.rb --exclude="#{EXCLUDE_REGEXP}" --delete --progress -r #{directory} my.amazon.backup.bucket:#{directory}`
 end

I would like the output of the executed subprocess to be echoed to the terminal in real time (as opposed to having to wait until the subprocess returns). How do I do that?

Answer 1

If you don’t need for your code to see stdout, and it’s sufficient that a human sees it, than system is fine. If you need your code to see it, there are numerous solutions, popen being the simplest, giving your code access to stdout, and Open3 giving your code access to both stdout and stderr. See: Ruby Process Management