The Debian packaging system relies on your local system having some idea of what packages are available. This is initialised when you install your system. You will generally need to update this list of packages with what is currently available from the Debian archives for downloading. If you are staying with the stable release you generally only need to update the list of available packages once. The following command is used to update the information about what is available for downloading:
$ wajig update (dpkg update)
(In brackets after the wajig command is the underlying command that wajig calls upon to perform the operation.)
This uses entries in the file /etc/apt/sources.list to know where to get the list of available packages from and which release of Debian you wish to follow. You can edit this file with:
$ wajig editsources (editor /etc/apt/sources.list)
This will use the system's default editor, but you can change which editor is the default with the command:
$ wajig updatealts editor (update-alternatives --config editor)
(Use the command wajig listalts for a list of things for which alternatives exist, and hence can be updated.)
You need to understand the format of the file /etc/apt/sources.list as explained in the manual page:
$ man sources.list
It is pretty straightforward and we will see examples in the next section.