DPKG / APT-GET basics

dpkg-query -W "*spam*"    ... simple output
dpkg-query -l "*spam*"      ... detailed output

see apt-cache search below for a more intense search

dpkg-query -s spampd        ... list status of package
dpkg-query -L spampd        ... list all files of this package

dpkg-query -S smb.conf

dpkg -r spampd   ... remove the package
dpkg -P spampd   ... purge the package including config-files

dpkg -i packagefile.deb
dpkg -i cyrus*
dpkg -iR thisfolder/

apt-get install rdate

apt-get update

after running apt-get update you run

apt-get update

apt-cache search NAME

NAME can be just part of the name, but you must not use wildcards here !!!

example:

wget http://ftp.sara.nl/debian_sara.asc
apt-key add debian_sara.asc
apt-key list