Program sfderiv | First derivative with a maximally linear FIR differentiator. 
[SYNOPSIS]
sfderiv < in.rsf > out.rsf order=6 scale=n
[COMMENTS]

May 2012 program of the month:
http://ahay.org/blog/2012/05/01/program-of-the-month-sfderiv/

[PARAMETERS]
int     | order | =6 |   | 	filter order 
bool    | scale | =n |  [y/n] | 	if scale by 1/dx 
[DIRECTORY]
system/generic
