GRASS has extensive and brilliant documentation, but I still have a bit of trouble using v.net.path. in the example for shortest path, it says: "
#Shortest path: ID as first number, then cat1 and cat2 echo "1 1 2" | v.net.path myroads_net_time alayer=3 nlayer=2 out=mypath"
I've had trouble understanding what ID is; my table has 'cat' as it's primary key, but there is no ID column.
P.S. I'm using Grass 6.4 on Mac.