Tools that know they will take a long time often come with a built-in progress indicator, but there are other utilities on Linux that often leave the user frustratedly tapping their fingers, wondering how much longer they will have to wait.
Luckily, there is a nifty little tool called pv that will donate a progress bar to any program that can read from standard input or a pipe. pv probably stands for pipe viewer.
1. Simple example: figure out how long an md5sum will take:
pv eternal.avi |md5sum
will display something like
96.5MB 0:00:05 [25.3MB/s] [=======> ] 9% ETA 0:00:48
Posted by Constantin 
