dpkg/apt question

["Preston Boyington" <PBoyington@polyengineering.com>]

i have "inherited" an existing debian box and want to change the packages to suit me and the office that it will now be used.

i would like to take the installed packages listed from:

dpkg --get-selections > packages.txt

and edit the file to reflect what i actually want/need on the box.

after i get the edited list prepared, is there a command i can issue that will instruct apt or dpkg to add/remove the programs to reflect my changes?

on a fresh install i would do:

dpkg --set-selections < packages.txt

then:

apt-get install

but i don't know the command to do this from a existing setup.

would someone shed some light on this for me?

thanks,
Preston