Keep in mind: many things you want to do in grep you can do in awk. Or, maybe there is just a better way. I learned grep early on and have been forcing it to do things it wasn’t really designed to do, so here I will actually be listing solutions using other tools – tools that may be better designed for the task at hand.
Display Line Number of a Match
awk:
awk '/textstring/ {print FNR}' textfile
sed:
sed -n '/pattern/=' filename