Re: How to find installed packages not in APT?

[Tim Woodall <debianuser@woodall.me.uk>]

On Mon, 3 Feb 2025, Loren M. Lang wrote:

> On Mon, Feb 03, 2025 at 11:09:58AM +0000, Andy Smith wrote:
> > Hi Loren,
> >
> > On Sun, Feb 02, 2025 at 11:29:45PM -0800, Loren M. Lang wrote:
> > > I am looking for a way to find all packages that have been installed on
> > > my system according to dpkg, but don't have a matching entry in Apt.
> >
> > Packages installed with dpkg -i *do* show in apt, so can you be more
> > specific about what you are looking for?
>
> Yes, I am specifically trying to find packages that don't match entries
> from the package lists downloaded in main, non-free, contrib, etc.
> Basically, I want to identify any software that I couldn't reinstall on
> a fresh install of Debian from the official Debian archives.

I forget which option it is but
apt list "~c"

or

apt list "~o"

is probably close to what you want - I think it's the second. The first
I think is for uninstalled packages that have config left behind but I
didn't make notes.

IIRC this also works:

apt list --installed | grep ,local

which I used for ages before I discovered the "~o" option. The comma is
important to filter out any packages that have local in their name, for
example:
libencode-locale-perl/stable,now 1.05-3 all [installed,automatic]