Packages#
Misc Package Commands#
List installed packages [1]:
apt list --installed
Information on installed package [2]:
dpkg -s <PACKAGE>
Information on non-installed package:
dpkg --print-avail <PACKAGE>
Find package which provides file [3]:
apt-file search <FILE>
Packages Held Back#
On day of 16.10 (Yakkety) release, doing apt-get upgrade seemed to update kernel from 4.4.0-42 to 4.4.0-43. GRUB now defaults to 43, but all hardware support is gone (usb, wifi, ethernet, etc).
When booting back into 42 and doing apt-get upgrade, now seeing:
The following packages have been kept back:
linux-generic linux-headers-generic linux-image-generic linux-signed-generic linux-signed-image-generic
Kept back implies that newer versions of the listed packages cannot be installed without breaking current dependencies:
- 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.
—apt-get man page
Would seem that apt-get upgrade is trying to upgrade the kernel packages (linux-generic, linux-headers-generic, etc) to 43, but has realised that doing so would screw 42 and as such aborts. Not sure why it’s trying to upgrade to 43, but probably due to Yakkety release. Think those kernel packages are virtual and should contain different things for Yakkety and Xenial. Maybe someone screwed up the release upstream?
… indeed would seem to be the case. An apt-get upgrade at a later date seems to have fixed the problem.
Ignoring ucf-dist File#
For a while now, have been getting following notification during apt-get update:
N: Ignoring file '20auto-upgrades.ucf-dist' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension
Reading around a little, found out that is due to conflicting APT configuration files.
APT configuration is done via a series of distributed configuration files all held in /etc/apt/apt.conf.d directory [4]. When a package updates an APT config file, the ucf (Update Configuration Files) utility is called to prompt the user whether to keep the old config file or switch to the new one. Regardless of the given answer, the original configuration file (before update) is copied to a *.ucf-dist suffixed file. The configurations contained within this file is ignored by apt-get update due to the added extension, generating the above notification [5].
As such, the retained original config file can be compared to the active config file, and if not needed can be safely deleted.