How does one determine packages added after installation?

[Luis Paulo]

On Fri, Oct 15, 2010 at 16:24, Tom Browder <tom.browder at gmail.com> wrote:
> <snip>
> My purpose is so that I can ensure a co-worker has the same package
> setup as I so our environments are identical.  I know I can do this by
> comparing his installed package list versus mine. but it would be
> easier if I could just tell him what I added after a default
> installation. <snip>


$ dpkg -l
will list all packages installed packages

looking for a format option at man dpkg, I found this under examples:

       To make a local copy of the package selection states:
            dpkg --get-selections >myselections

       You might transfer this file to another computer, and install
it there with:
            dpkg --clear-selections
            dpkg --set-selections <myselections

       Note that this will not actually install or remove anything,
but just set the selection state on  the
       requested  packages.  You  will  need  some  other  application
 to actually download and install the
       requested packages. For example, run apt-get dselect-upgrade.

Never tried it, though.

Regards
Luis