The file /etc/setup/installed.db lists all the packages, and only the packages that you have currently installed, together with their version numbers. If you ara happy with that installation (and it sounds as though you are: your post does not mention any requirement for re-installation, it explicitly states how tedious that would be) then it looks to me as though the best approach would be to edit that file into a .bat file to be run from outside Cygwin, or a script to be run from within Cygwin, that will (1) move the files you want to keep to a new location, (2) delete what's left, (3) rename new location to old. (Or have the effect of (1) - (3), however you manage the detail.) Any good, do you think?
Fergus If you wanted to run a fresh installation with just these packages, and without the effort of picking them, then this too can be contrived, but that's another story. Do you?
