How to follow the progress of a linux command?

Question

I am currently working with a large data set where even the file format conversion takes at least an hour per subject and as a result I am often unsure whether my command has been executed or the program has frozen. I was wondering whether anyone has a tip to how to follow the progress of the commands/scripts I am trying to run in linux?

Your help will be much appreciated.

Answer 1

If the long-lasting command produces some output in a file foo.out, you could do watch ls -l foo.out or tail -f foo.out

You could also list /proc/$(pidof prog)/fd to find out the opened files of some prog