Solución 1:
Desde la página man de apt-get,
-s, --simulate, --just-print, --dry-run, --recon, --no-act No action; perform a simulation of events that would occur but do not actually change the system. Configuration Item: APT::Get::Simulate. Simulation run as user will deactivate locking (Debug::NoLocking) automatic. Also a notice will be displayed indicating that this is only a simulation, if the option APT::Get::Show-User-Simulation-Note is set (Default: true). Neither NoLocking nor the notice will be triggered if run as root (root should know what he is doing without further warnings by apt-get). Simulate prints out a series of lines each one representing a dpkg operation, Configure (Conf), Remove (Remv), Unpack (Inst). Square brackets indicate broken packages and empty set of square brackets meaning breaks that are of no consequence (rare).
Así que asegúrate de apt-get -s upgrade .
Si desea actualizar ciertos paquetes, simplemente apt-get install <package name> y lo actualizará si ya está instalado. Sin embargo, también tendrá que actualizar todas las dependencias y, dependiendo de cuáles sean, eso puede convertirse en una cascada de muchas actualizaciones.
Si estoy atrasado en las actualizaciones de paquetes, haré un apt-get install en algunos de los más importantes (quizás php, apache2, etc.) para poder mantenerlos contenidos y revisar cualquier problema, y luego apt-get upgrade después de que termine.
Solución 2:
Yo uso apt list --upgradable .
La siguiente alternativa es apt-get --simulate upgrade . (basado en @EightBitTony)
Aquí hay resultados de diferentes opciones (espero que ayude a alguien):
[email protected]:~$ apt list --upgradable
Listing... Done
kubernetes-cni/kubernetes-xenial 0.7.5-00 amd64 [upgradable from: 0.6.0-00]
N: There are 3 additional versions. Please use the '-a' switch to see them.
[email protected]:~$ apt-get --simulate upgrade
NOTE: This is only a simulation!
apt-get needs root privileges for real execution.
Keep also in mind that locking is deactivated,
so don't depend on the relevance to the real current situation!
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
kubernetes-cni
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Inst kubernetes-cni [0.6.0-00] (0.7.5-00 kubernetes-xenial:kubernetes-xenial [amd64])
Conf kubernetes-cni (0.7.5-00 kubernetes-xenial:kubernetes-xenial [amd64])
[email protected]:~$ apt-get -u upgrade --assume-no
E: Could not open lock file /var/lib/dpkg/lock-frontend - open (13: Permission denied)
E: Unable to acquire the dpkg frontend lock (/var/lib/dpkg/lock-frontend), are you root?
[email protected]:~$ sudo apt-get -u upgrade --assume-no
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
kubernetes-cni
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 6,473 kB of archives.
After this operation, 4,278 kB of additional disk space will be used.
Do you want to continue? [Y/n] N
Abort.
[email protected]:~$ sudo apt-get -u -V upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
Calculating upgrade... Done
The following packages will be upgraded:
kubernetes-cni (0.6.0-00 => 0.7.5-00)
1 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
Need to get 6,473 kB of archives.
After this operation, 4,278 kB of additional disk space will be used.
Do you want to continue? [Y/n] n
Abort.
Solución 3:
Para enumerar los paquetes que se actualizarán con sus versiones:
$ sudo apt-get -u -V upgrade
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages have been kept back:
mysql-client-5.5 (5.5.29-0ubuntu0.12.04.2 => 5.5.32-0ubuntu0.12.04.1)
mysql-server-5.5 (5.5.29-0ubuntu0.12.04.2 => 5.5.32-0ubuntu0.12.04.1)
mysql-server-core-5.5 (5.5.29-0ubuntu0.12.04.2 => 5.5.32-0ubuntu0.12.04.1)
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.
Luego, puede elegir qué actualizar:
$ sudo apt-get --only-upgrade install mysql-client-5.5
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
firefox-globalmenu
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
libterm-readkey-perl
The following NEW packages will be installed:
libterm-readkey-perl
The following packages will be upgraded:
mysql-client-5.5
1 upgraded, 1 newly installed, 0 to remove and 2 not upgraded.
Need to get 8,123 kB of archives.
After this operation, 139 kB of additional disk space will be used.
Do you want to continue [Y/n]? Y
Get:1 http://us.archive.ubuntu.com/ubuntu/ precise/main libterm-readkey-perl i386 2.30-4build3 [28.4 kB]
Get:2 http://us.archive.ubuntu.com/ubuntu/ precise-updates/main mysql-client-5.5 i386 5.5.32-0ubuntu0.12.04.1 [8,094 kB]
...
Si hay dependencias antiguas que se eliminan, puede ejecutar apt-get autoremove y, como puede ver, se le pedirá que instale cualquier nueva dependencia. El --only-upgrade flag no es necesario, pero está bien si quiere asegurarse de no instalar accidentalmente un paquete nuevo en lugar de actualizar uno existente, es decir, tiene uno de esos momentos y escribe accidentalmente el paquete incorrecto:
$ sudo apt-get --only-upgrade install mysql-proxy
Reading package lists... Done
Building dependency tree
Reading state information... Done
Skipping mysql-proxy, it is not installed and only upgrades are requested.
The following package was automatically installed and is no longer required:
firefox-globalmenu
Use 'apt-get autoremove' to remove them.
0 upgraded, 0 newly installed, 0 to remove and 2 not upgraded.