Upgrading to Ubuntu 20, *how* to back up?

[David Fletcher]

On Tue, 2020-04-28 at 15:20 +0200, Bo Berglund wrote:

> Interesting, especially the way to extract what was installed via apt.
> However when I try this on the command line on Ubuntu 18.04 I get a
> strange result (without sending the output to a file):
> 
> ~$ aptitude search '~i !~M' | tr -s ' ' | cut -f 2 -d ' '

I used
sudo apt-get install aptitude

plus the email system has wrapped the aptitude search command onto a
second line. You need to get it all!

I got into the habit of using aptitude a long time ago. It's generally
the first thing I install, next I use it to install joe. Because I like
joe.

> So I changed aptitude to apt and got this:
> 
> $ apt search '~i !~M' | tr -s ' ' | cut -f 2 -d ' '
> 
> WARNING: apt does not have a stable CLI interface. Use with caution in
> scripts.
> 
> Sorting...
> Text
> 
> Seems like I have gotten it all wrong here.
> I thought apt was a short form of aptitude....

There's a little article about it here...
https://en.wikipedia.org/wiki/Aptitude_(software)

Rather busy at the moment, duplicating my mail server setup on a new
20.04 system, making up new power cabling, etc.

Dave