Apt package handling

list installed packages with post in their name

dpkg-query -l '*post*'

show detailed desc of postfix package

apt-cache show postfix

search in package name and desc for xxx

apt-cache search postfix

update local apt package database

apt-get update

update entire system

apt-get upgrade

upgrade system to a new release

apt-get -u dist-upgrade

install postfix package

apt-get [--reinstall] install postfix

reinstall installed postfix package

apt-get --reinstall install postfix

remove postfix package

apt-get remove postfix

remove postfix package and config files

apt-get --purge remove postfix

clean up /etc after deinstallation

find /etc/ -name '*grey*' -ok rm -f {} \;