refresh this list of all available software and the versions of that
software from all available sources so that it can take advantage of
the most recent software updates and additions. Note that "apt update"
does not actually install any software, it simply informs the system
of what is available.
download and install any available new versions of software that is
already installed on the system. If a new version of a package
requires an additional package to be installed, or if it requires an
existing package to be removes, "apt upgrade" will kindly let you know
that the upgrade is being held back. Under no circumstances will it
install new packages or remove any existing packages.
This command will perform the same function as "apt upgrade" however
it will install additional packages that new versions depend on, and
it will remove packages that cause conflicts.
install any available package by including the package name after the command
Removing software is just the same as installing it except for one
word. Configuration files from the removed application will stay on
the system in case you later decide to reinstall the application.
There's really not much to it.
This command is just like "apt remove" however it will remove any
configuration files associated with the application being removed as
sudo dpkg -i
handles downloaded software packages from the terminal.