Computing streamlines for 2D pipe from command line
 

I have simulated a 2D pipe and would like to compute automatically form the command line (not paraview) a couple of streamlines. Unfortunately, I'm new to OpenFoam and new to its post-processing functionalities.

While searching I stumbled upon this and the function example therein. However, I neither know how to execute such a function nor how to adapt it to my needs.

I computed the 2D pipe using simpleFoam and obtained U and p fields. I would like to compute the streamlines from beginning of the pipe till its end (inflow till outflow). The part about "uniformCoeffs" in the example function I guess I understand and can modify to my needs. But how do I have to change e.g. "lifeTime", "trackLength" and "nSubCycle" ? And how to run this function?

Thanks a lot for your help in advance.