Debian APT - some questions

Question

1. How can I check which packages are currently installed?
2. How can I find all packages that are not installed?
3. Is possible to uninstall package and all files of that package (config, temporaries, etc.)?

I'm using Debian Squeeze 6.0.7.

Answer 1

1. dpkg -l
2. well there will be A LOT of NOT installed packages.. why would you want to do that? btw, the command apt-cache pkgnames will provide you the list of ALL available packages in the repository added in your sources.list configuration
3. apt-get remove will remove the installed package, but you'll normally keep the configurations, which is the desired behaviour usually.

further info: http://www.cyberciti.biz/howto/question/linux/dpkg-cheat-sheet.php