sfnmodips (2.0-git)
Slopes for constant-velocity normal moveout.

        sfnmodips < cmp.rsf > dip.rsf offset=offset.rsf half=y nv= v0= dv= CDPtype= slowness=n squared=n h0=0. extend=4

int CDPtype=

float dv=
step in velocity
int extend=4
trace extension
float h0=0.
reference offset
bool half=y [y/n]
if y, the second axis is half-offset instead of full offset
int nv=
number of velocities
string offset=
auxiliary input file name
bool slowness=n [y/n]
if y, use slowness instead of velocity
bool squared=n [y/n]
if y, the slowness or velocity is squared
float v0=
first velocity