File listing all the manually installed packages?

[Adam Funk]

On 2014-05-09, Bill Mills-Curran wrote:

> On Fri, May 09, 2014 at 02:55:52PM +0100, Adam Funk wrote:
>> 
>> Is there a file on an Ubuntu system that I can grep to find all the
>> manually installed packages?
>> 
>> Normally I'd expect grep the output of dpkg or aptitude for this sort
>> of thing, but the machine in question died; I copied the entire hard
>> drive onto a USB drive & need the information to make sure I reinstall
>> Ubuntu (for someone else) on the new machine without anything missing.

> Have you tried the --admindir option on dpgk-query?  The man page
> suggests (to me, anyway) that you could access the db from the old
> disk.
>
>        --admindir=dir
>               Change the location of the dpkg database. The  default
>               location
>               is /var/lib/dpkg.

Excellent!  Unfortunately, AFAICT, dpkg -l doesn't have any way to
distinguish manually & automatically installed packages, & what I'd
really like is a list of purely the manually installed ones.  I've
come across 'aptitude search '!~M ~i' --- is it possible to point that
at an alternative location for '/var/lib/aptitude/pkgstates', for
example?

Thanks,
Adam