How to show make visible a tftp transfer progress in a script

I have a client app that launch in async mode a bash script that send a file to a TFTP server. The issue is that I don't know how to show user the progress of this transfer, worst of all this operation is about 2-3 minutes long. My workaround was to use --trace option with atftp command and put it in a file and every n-second I read this file to show user the progress in %. atftp -p -l test.png --verbose --trace 192.168.1.1 > progress.txt atftp -p --trace -l test.png 192.168.1.1 | tee progress.txt There is a problem, strangely atftp doesn't seems to put anything on that file, meanwhile classic tftp did it. Did I missing something about atftp or did you suggest other way to retrieve progress status of this operation? Unfortunately I'm on a Debian Squeeze on a very legacy configuration. Thanks in advance and have a nice day. EDIT: first workaround found, I put tftp interactive mode (so I can active trace) in a script and pipe out the output of that script. Now I must find a way to read only the last row data every n-seconds.