How do I find out what packages I have currently installed?

[Kai Sterker <ksterker@geekmail.de>]

Hello everybody,

I've got a question concerning Debian I found no answer for in the
manuals; perhaps you can help me:

Is it possible to see what packages I have installed, so I can

(a) download all of them in one go and
(b) reinstall exactly those package after erasing all of my HD

For example, if I make dist-upgrade, I guess only those packages are
downloaded that are no longer up-to-date on my box, which might not be all.

Even if all packages would be downloaded, I wouldn't know how to make sure 
that all of them are installed when I do a fresh setup _without_ manually
selecting every single package.


For example, SuSE allows to save a package configuration (to a floppy disk
among others). And when doing a new install, I can load that config from the
disk, so I need not go through package selection again. Is something similar
possible with Debian too? 

Thing is, I'll have to completely erase my HD, and I want to minimize the
time to setup everything to my liking afterwards.


Thanks for your help,

Kai