If you mean "How do I show progress of the system call" the general answer pretty much is "You can't". To show a sensible progress bar you have to have some way to provide a progress update that indicates how far through the process is. In the general case for a system call you can't do that. At best you could estimate the time that may be required and show a progress bar based on time (or similarly for an external measure of the progress - target file size for example) in a forked process. That's a pretty hairy and unsatisfactory solution though.