fivi is a tool do display information about the amount of data read and written by filters. filters are programs like bzip2 or nl, which read a stream of input data on their stdin, mangle this data (of course they don't have to...) and output it to their stdout.
fivi can show information like the wall clock time already spend computing, the amount of read and written data, the relation of these sizes, and if it knows the total file size of the input data, it can take a guess at what the resulting data size will be, and when the filter will be finished.
please be aware that fivi is alpha level software. The software is still in early development, all command line arguments are presumed to change some time before version 1.0, and you should not trust fivi with any valuable data, if at all.
latest version: fivi 0.2
fivi was written by Uli Martens.