I forgot to tell you how to save and restore for future reference.
Here they are.
------------------------------------------------------------ To save your installed list do this:
dpkg --get selections | grep -v deinstall > packagestateXXXXXXXX.txt
where XXXXXXXX is the current date. Or use your own convention. The grep -v deinstall removes entries of packages that are marked for removal.
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To later restore them do this:
dpkg --clear-selections dpkg --set-selections < packagestateXXXXXXXX.txt apt-get -u dselect-upgrade --purge
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Note this is all commandline stuff and assumes you are logged in as root. Simply prepend "sudo" to each line if you are not root. Note, also this is destructive. I believe it might remove and purge some software not on this list. I've never tried this so proceed at your own risk. Alternatively you could remove the --purge option to not purge any config files on anything it might remove.
There might be a utility out there to do this for you, but I dn't know of it.
Brian J