Eu adicionei um repositório backport ao apt's sources.list para obter uma aplicação:
deb http://ftp.uk.debian.org/debian/ wheezy-backports main
Resumindo: não consegui instalar o aplicativo corretamente, por isso desisti e removi essa linha do meu sources.list .
Mas desde então o apt está uma bagunça. Por algumas razões, o gnome foi parcialmente desinstalado no processo (eu joguei com synaptic e aptitude e, aparentemente, cometi um erro), mas não consigo reinstalá-lo:
sudo apt-get install gnome
....
The following packages have unmet dependencies:
gnome : Depends: gnome-core (= 1:3.4+7+deb7u1) but it is not going to be installed
Depends: nautilus-sendto (>= 3.0) but it is not going to be installed
Depends: gimp (>= 2.8) but it is not going to be installed
Depends: hamster-applet (>= 2.91.3) but it is not going to be installed
Depends: gnome-applets (>= 3.4) but it is not going to be installed
Recommends: browser-plugin-gnash but it is not going to be installed
E: Unable to correct problems, you have held broken packages.
Eu tentei (em muitas ordens diferentes):
apt-get update
apt-get upgrade
apt-get dist-upgrade
apt-get clean
apt-get -f install gnome
apt-get install -f
dpkg --configure -a
mas nenhum deles funcionou.
Eu também corri sudo dpkg --get-selections | awk '{if ($2 == "hold") print $0;}' para saber mais sobre os pacotes, mas ele não retorna nada.
EDIT 1 - informações adicionais
$ sudo apt-get -f install
Reading package lists... Done
Building dependency tree
Reading state information... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.
$ sudo apt-cache policy gnome-core nautilus-sendto gimp hamster-applet gnome-applets gnome
gnome-core:
Installed: (none)
Candidate: 1:3.4+7+deb7u1
Version table:
1:3.4+7+deb7u1 0
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
nautilus-sendto:
Installed: (none)
Candidate: 3.0.3-2+b1
Version table:
3.0.3-2+b1 0
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
gimp:
Installed: (none)
Candidate: 2.8.2-2+deb7u1
Version table:
2.8.2-2+deb7u1 0
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
500 http://security.debian.org/ wheezy/updates/main amd64 Packages
100 /var/lib/dpkg/status
hamster-applet:
Installed: (none)
Candidate: 2.91.3+git20120514.b9fec3e1-1
Version table:
2.91.3+git20120514.b9fec3e1-1 0
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
gnome-applets:
Installed: (none)
Candidate: 3.4.1-3
Version table:
3.4.1-3 0
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
gnome:
Installed: (none)
Candidate: 1:3.4+7+deb7u1
Version table:
1:3.4+7+deb7u1 0
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
EDIT 2 - dpkg-l
~$ sudo dpkg -l gnome-core nautilus-sendto gimp hamster-applet gnome-applets gnome
Desired=Unknown/Install/Remove/Purge/Hold
| Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend
|/ Err?=(none)/Reinst-required (Status,Err: uppercase=bad)
||/ Name Version Architecture Description
+++-=================================================-=============================-=============================-=======================================================================================================
rc gimp 2.8.2-2+deb7u1 amd64 The GNU Image Manipulation Program
un gnome <none> (no description available)
un gnome-applets <none> (no description available)
un nautilus-sendto <none> (no description available)
dpkg-query: no packages found matching gnome-core
dpkg-query: no packages found matching hamster-applet
EDITAR 3 - apt-get policy
$ sudo apt-cache policy
Package files:
100 /var/lib/dpkg/status
release a=now
500 http://apt.postgresql.org/pub/repos/apt/ wheezy-pgdg/main amd64 Packages
release o=apt.postgresql.org,a=wheezy-pgdg,n=wheezy-pgdg,l=PostgreSQL for Debian/Ubuntu repository,c=main
origin apt.postgresql.org
500 http://www.deb-multimedia.org/ testing/non-free amd64 Packages
release v=None,o=Unofficial Multimedia Packages,a=testing,n=jessie,l=Unofficial Multimedia Packages,c=non-free
origin www.deb-multimedia.org
500 http://www.deb-multimedia.org/ testing/main amd64 Packages
release v=None,o=Unofficial Multimedia Packages,a=testing,n=jessie,l=Unofficial Multimedia Packages,c=main
origin www.deb-multimedia.org
500 http://downloads-distro.mongodb.org/repo/debian-sysvinit/ dist/10gen amd64 Packages
release v=dist,o=10gen,a=10gen,n=dist,l=10gen,c=10gen
origin downloads-distro.mongodb.org
500 http://security.debian.org/ wheezy/updates/main Translation-en
500 http://security.debian.org/ wheezy/updates/main amd64 Packages
release v=7.0,o=Debian,a=stable,n=wheezy,l=Debian-Security,c=main
origin security.debian.org
500 http://ftp.uk.debian.org/debian/ wheezy/main Translation-en
500 http://ftp.uk.debian.org/debian/ wheezy/main amd64 Packages
release v=7.4,o=Debian,a=stable,n=wheezy,l=Debian,c=main
origin ftp.uk.debian.org
Pinned packages: