Show information about a data transfer

 Bar is a simple tool to process a stream of data and print a display for
 the user on stderr showing (a) the amount of data passed, (b) the
 throughput of the data transfer, and, if the total size of the data stream
 is known, (c) estimated time remaining, percent complete, and a progress bar.
 .
 Bar was originally written for the purpose of estimating the amount of time
 needed to transfer large amounts (many, many gigabytes) of data across a
 network. (Usually in an SSH/tar pipe.)