I have never used SRAM gear before…but I need to replace the rear gear cable.

I have SRAM x7 shifters, I am assuming its a fairly easy task ?

yes. Take cover off and easy to see how the cable removes – think you need to make sure you are either in top or bottom but cant recall which. Springs should not fly apart when opened but may apparently never have with mine

dead easy, pretty much the same as shimano,put in smallest cog on back, undo plastic blanking screw pull old cable out, thread new cable in, do up cable re index gears, done

I thought so, I guess they will just use standard shimano gear cables ?

gear cables are a standard size ….it is not a shimano thing so yes

Standard gear cables are indeed standard. The non-standard ones (XTR) are a little bit thinner.