Ubuntu (dpkg): dpkg --get-selections | grep -v deinstall
Cygwin: dpkg --get-selections> installedPackagesDate.txt OR cygcheck -c -d|sed -e "1,2d" -e 's/ .*$//' > installedPackagesDate.txt
Cygwin restore: dpkg --set-selections< installedPackagesDate.txt&& apt-get dselect-upgrade