sudo apt update vs. sudo apt full-upgrade?

[fhins]

I always have always used sudo apt update, and sudo apt full-upgrade all the time, until I read some article about the difference, which was not really recommended to use sudo apt full-upgrade every time for normal updates. So my question is at what point are you suppose to use sudo apt full-upgrade?

[claydoh]

You need to use both, as they do different things.

apt update refreshes your package list.
apt full-upgrade install the updates found from apt update.

You need to use both, as they do different things.


What article says this is wrong?





Now, in recent years, the command has changed, from the old apt-get to just apt
The confusions come from the differences between how Debian and Ubuntu updates happen. This was more prominent back when apt-get was the norm. Using apt-get upgrade in Ubuntu would not install all the available updates and their new dependencies, whereas in Debian this was the correct usage, as there would not be new dependencies, by design. apt-get dist-upgrade was the correct way to install updates in Ubuntu, while on Debian, it was part of the methods used to upgrade that distro to a newer release. just as the command would seem to indicate.


now, with the move to plain 'apt', there still is a difference. Ubuntu uses apt full-upgrade over simply apt upgrade. Most of the time, running the latter in Ubuntu is just fine, but there will be times when this won't install all the updates, just like the old apt-get upgrade would not, but not to the extreme.

For people who use PPAs, and particularly Kubuntu users who use their Backports and/or Updates PPAs, if you don't use full-upgrade you won't get all the new deps, and many packages won't be installed, and thus creating conflicts and breakages.

Just use full-upgrade. It is what Discover/Gnome Software/packagekit use under the hood, and is how Ubuntu was set up to use. There is zero harm in doing so.

[Snowhog]

When unsure of a command and it's options, just look at its man page.

man apt

...
update (apt-get(8))
update is used to download package information from all configured sources. Other
commands operate on this data to e.g. perform package upgrades or search in and
display details about all packages available for installation.

upgrade (apt-get(8))
upgrade is used to install available upgrades of all packages currently installed on
the system from the sources configured via sources.list(5). New packages will be
installed if required to statisfy dependencies, but existing packages will never be
removed. If an upgrade for a package requires the remove of an installed package the
upgrade for this package isn't performed.

full-upgrade (apt-get(8))
full-upgrade performs the function of upgrade but will remove currently installed
packages if this is needed to upgrade the system as a whole.

[claydoh]

Actually:

DESCRIPTION
apt provides a high-level commandline interface for the package management system. It is intended as an end user
interface and enables some options better suited for interactive usage by default compared to more specialized APT tools
like apt-get(8) and apt-cache(8).

Much like apt itself, its manpage is intended as an end user interface and as such only mentions the most used commands
and options partly to not duplicate information in multiple places and partly to avoid overwhelming readers with a
cornucopia of options and details.

update (apt-get(8))
update is used to download package information from all configured sources. Other commands operate on this data to
e.g. perform package upgrades or search in and display details about all packages available for installation.

upgrade (apt-get(8))
upgrade is used to install available upgrades of all packages currently installed on the system from the sources
configured via sources.list(5). New packages will be installed if required to satisfy dependencies, but existing
packages will never be removed. If an upgrade for a package requires the removal of an installed package the upgrade
for this package isn't performed.

full-upgrade (apt-get(8))
full-upgrade performs the function of upgrade but will remove currently installed packages if this is needed to
upgrade the system as a whole.

[fhins]

So really there is no harm just to do a sudo apt update and sudo apt-full upgrade, as to why would you want the keep the old packages to begin with? Even later on when you do a sudo apt full upgrade, you're going to remove the old packages any way. So why not just do a sudo apt update, and sudo apt full-grade? This is so confusing!

[claydoh]

It is confusing because Ubuntu does some things a bit differently than it's parent Debian does.
Debian, who created apt and deb packages, does not cater to constant changes, but heavily favors few changes and greater stability, and lower chances of an update breaking things. it is why Debian is so 'behind'.