Por que não consigo instalar esses pacotes?

Question

Eu quero instalar a biblioteca curl no Ubuntu 12.04 LTS. Para isso eu uso o seguinte comando sudo apt-get instala libcurl4-openssl-dev. mas eu tenho os erros como

    ajay@ajay-K54L:~$ sudo apt-get install libcurl4-openssl-dev
    [sudo] password for ajay: 
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    Some packages could not be installed. This may mean that you have
    requested an impossible situation or if you are using the unstable
    distribution that some required packages have not yet been created
    or been moved out of Incoming.
    The following information may help to resolve the situation:

    The following packages have unmet dependencies:
     libcurl4-openssl-dev : Depends: libkrb5-dev but it is not going to be installed
                            Depends: librtmp-dev but it is not going to be installed
    E: Unable to correct problems, you have held broken packages.

Sempre que eu tento instalar dependências, isso mostra que os pacotes já estão instalados:

   ajay@ajay-K54L:~$ sudo apt-get install -f libkrb5-dev
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    Some packages could not be installed. This may mean that you have
    requested an impossible situation or if you are using the unstable
    distribution that some required packages have not yet been created
    or been moved out of Incoming.
    The following information may help to resolve the situation:

    The following packages have unmet dependencies:
     libkrb5-dev : Depends: krb5-multidev (= 1.10+dfsg~beta1-2) but it is not going to be installed
    E: Unable to correct problems, you have held broken packages.
    ajay@ajay-K54L:~$ sudo apt-get install -f krb5-multidev
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    Some packages could not be installed. This may mean that you have
    requested an impossible situation or if you are using the unstable
    distribution that some required packages have not yet been created
    or been moved out of Incoming.
    The following information may help to resolve the situation:

    The following packages have unmet dependencies:
     krb5-multidev : Depends: libkrb5-3 (= 1.10+dfsg~beta1-2) but 1.10+dfsg~beta1-2ubuntu0.3 is to be installed
                     Depends: libk5crypto3 (= 1.10+dfsg~beta1-2) but 1.10+dfsg~beta1-2ubuntu0.3 is to be installed
                     Depends: libgssapi-krb5-2 (= 1.10+dfsg~beta1-2) but 1.10+dfsg~beta1-2ubuntu0.3 is to be installed
    E: Unable to correct problems, you have held broken packages.
    ajay@ajay-K54L:~$ sudo apt-get install -f libkrb5-3
    Reading package lists... Done
    Building dependency tree       
    Reading state information... Done
    libkrb5-3 is already the newest version.
    0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

O que preciso fazer?

Eu tentei seguir o comando

apt-cache policy libkrb5-3 krb5-multidev libk5crypto3 libgssapi-krb5-2 libcurl4-openssl-dev

e isso me dá saída como:

ibkrb5-3:
  Installed: 1.10+dfsg~beta1-2ubuntu0.3
  Candidate: 1.10+dfsg~beta1-2ubuntu0.3
  Version table:
 *** 1.10+dfsg~beta1-2ubuntu0.3 0
        100 /var/lib/dpkg/status
     1.10+dfsg~beta1-2 0
        500 http://in.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
krb5-multidev:
  Installed: (none)
  Candidate: 1.10+dfsg~beta1-2
  Version table:
     1.10+dfsg~beta1-2 0
        500 http://in.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
libk5crypto3:
  Installed: 1.10+dfsg~beta1-2ubuntu0.3
  Candidate: 1.10+dfsg~beta1-2ubuntu0.3
  Version table:
 *** 1.10+dfsg~beta1-2ubuntu0.3 0
        100 /var/lib/dpkg/status
     1.10+dfsg~beta1-2 0
        500 http://in.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
libgssapi-krb5-2:
  Installed: 1.10+dfsg~beta1-2ubuntu0.3
  Candidate: 1.10+dfsg~beta1-2ubuntu0.3
  Version table:
 *** 1.10+dfsg~beta1-2ubuntu0.3 0
        100 /var/lib/dpkg/status
     1.10+dfsg~beta1-2 0
        500 http://in.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages
libcurl4-openssl-dev:
  Installed: (none)
  Candidate: 7.22.0-3ubuntu4
  Version table:
     7.22.0-3ubuntu4 0
        500 http://in.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

    

Answer 1

A saída que você forneceu em apt-cache policy confirma minha suspeita sobre listas desatualizadas.

Para o exemplo de krb5-multidev em 12.04, você deve ver a versão 1.10+dfsg~beta1-2ubuntu0.3 como candidata fornecida por precise-updates .

krb5-multidev:
  Installed: 1.10+dfsg~beta1-2ubuntu0.3
  Candidate: 1.10+dfsg~beta1-2ubuntu0.3
  Version table:
 *** 1.10+dfsg~beta1-2ubuntu0.3 0
        500 http://nl.archive.ubuntu.com/ubuntu/ precise-updates/main amd64 Packages
        500 http://security.ubuntu.com/ubuntu/ precise-security/main amd64 Packages
        100 /var/lib/dpkg/status
     1.10+dfsg~beta1-2 0
        500 http://nl.archive.ubuntu.com/ubuntu/ precise/main amd64 Packages

Então, como já sugeri nos comentários, corra

sudo apt-get update

E você deve estar pronto (tente novamente a instalação e também atualize seu sistema corretamente!).