This is a really nice tool I didn't knew something like that exists. How many times I was wondering how the progress of loading a sqldump was.

man pv

pv shows the progress of data through a pipeline by giving information such as time elapsed, percentage completed (with progress bar), current throughput rate, total data transferred, and ETA.
To use it, insert it in a pipeline between two processes, with the appropriate options.  Its standard input will be passed through to its standard output and progress will be shown on standard error.