ubuntu 12.04 LTS how to avoid GRUB update
silver.bullet at zoho.com
Thu Jan 14 10:37:03 UTC 2016
On Thu, 14 Jan 2016 08:11:12 +0000 (UTC), Spyros Tsiolis wrote:
>Correct me if I am wrong but AFAIK, "upgrade" means
>upgrading to a more recent Ubuntu OS version
>while "update" means updating packages for the
>running / existing version.
No, you are mistaken.
update is used to resynchronize the package index files from
their sources." 
IOW it's a refresh of the data base of the available packages. It does
not update packages, it only syncs/updates the index/data base.
upgrade is used to install the newest versions of all
This installs upgraded versions of packages, but before doing this you
need to "update",otherwise the package management (apt) wouldn't know
that there are new packages.
dist-upgrade in addition to performing the function of
upgrade, also intelligently handles changing dependencies with
new versions of packages; apt-get has a "smart" conflict
resolution system, and it will attempt to upgrade the most
important packages at the expense of less important ones if
necessary. So, dist-upgrade command may remove some
It's the same as upgrade, but also manages packages as described. It's
not clear to me how recommended packages are handled by both kinds of
upgrade. However, a dist-upgrade might be not needed, but might be
useful, especially when using third party repositories. Theoretically
dist-upgrade is useful for release updates, but usually it's not used
for release upgrades, do-release-upgrade seems to be the recommended
way . I never upgraded from one to another release, so I would have
to read several sources myself, IOW the correctness of  might be ok,
or not ok.
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