[gradsusr] merging GRIB records

[Jakub Maroušek]

Hello everyone,
I'm coming with another tough question :-)

I want to plot a graph showing cloud cover depending on time and layer -- but 
there are four entries in my GRIB file, boundary/low/middle/high layer cloud 
cover. I need to display then in one graph, can I merge these entries to one 
entry containing all the data in different levels? Then, it would be easy to 
make a graph.

I noticed that f.e. temperature in different pressure levels is separated in the 
original GRIB file and is merged by g2ctl, but I can't persuade the script to do 
the same thing with cloud cover.

Thank you
Kuba M.