perhaps use the "split" tool after grep, to pull out the duration field?
Re Windows, I suspect trying to use DOS (and maybe even powershell) will be a relatively unhappy experience. You might like to install minGW and the associated Msys shell, which gives you a bash shell and enough of the unix utilities to do most things. Any command you need that isn't provided already can probably be found on the net somewhere. but grep, cut, split etc are all there. I think Cygwin is much the same kind of thing, but I have no experience of that. I use minGW to build all the CDP programs for Windows.