Been a while since I used NMRPipe. the -di means delete the unnecessary imaginary containing quadrants. If you need these quadrants later, e.g. for interactive phasing in SpinWorks, they can be recreated with a Hilbert transform.
I believe that -verb is "verbose" mode in which possibly useful diagnostics is outputted during the running of the script.
answered Sep 06 '16 at 11:23