apt-get update and apt-get dist-upgrade

[Fajar Priyanto]

On Tue, Sep 14, 2010 at 1:35 PM, Christopher Chan
<christopher.chan at bradbury.edu.hk> wrote:
>> apt-get dist-upgrade<-- will upgrade installed packages and may
>> remove some if necessary.
>
> Wrong. dist-upgrade stands for Distribution Upgrade which means not
> installing the latest packages for a release but upgarding to the next
> release.


upgrade
           upgrade is used to install the newest versions of all
packages currently installed
           on the system from the sources enumerated in
/etc/apt/sources.list. Packages
           currently installed with new versions available are
retrieved and upgraded; under no
           circumstances are currently installed packages removed, or
packages not already
           installed retrieved and installed. New versions of
currently installed packages that
           cannot be upgraded without changing the install status of
another package will be
           left at their current version. An update must be performed
first so that apt-get
           knows that new versions of packages are available.

dist-upgrade
           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 packages. The /etc/apt/sources.list
file contains a list of
           locations from which to retrieve desired package files. See
also apt_preferences(5)
           for a mechanism for overriding the general settings for
individual packages.

(dist-upgrade will upgrade INSTALLED packages and REMOVE some if
necessary. That's why most people imply it to ONLY upgrade the distro.
It can be used for ordinary upgrade TOO).