i do not need progress bar so i have not checked it at all - numeric representation of progress is just fine, well even better. As for tee/cmd - i believe executing copy x to y is actually executing cmd - or i do not know something?

Generally i need to copy a file which often is pretty big - can be over 1TB. So i need a way to execute copy and yet be able to read and write somewhere its progress. That write is quite crucial - it cant be just displayed. I need to be able to process it further on while copying is still occuring.