I want to be able to copy multiple files from multiple USB flash disks at the same time, being able to see current transfer rate of each simultaneously. It is part of performance testing for USB port on a specific board.
Using pv source > /dev/null from this answer, I am able to see the current transfer rate for one file. However, when I use pv source > /dev/null & to send the process into background and be able to run another transfer, the output from the pv command is not shown on stdout anymore.
It is to be noted that I am using minicom to connect to remote host using serial port, as the target board does not have it's own console output.
I am open to suggestions other than pv as well. The task is to do performance/bandwidth test of the USB port. I originally wanted to do it with cp but found out that it does not provide current transfer rate. I do not have a GUI otherwise could try it from that
EDIT: I have 2 problems with rsync:
1) The transfer rate is very slow (one-third of what I get with pv)
2) It somehow deletes the /dev/null after transferring around 300 MB, thus, stopping with an error