apt-get 更新/升级列表，无需更改任何内容

Question

我想查看哪些软件包可用于更新/升级而不实际更改任何文件，因为有些软件包我不想更新。那么是否可以在例外情况下进行 apt-get update 。

Answer 1

从 apt-get 手册页，

   -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).

所以只要确保你apt-get -s upgrade。

如果你想升级某些软件包，只要apt-get install <package name>它已经安装，它就会更新它。然而，它还必须更新所有依赖项，并且根据它们是什么，可以级联到许多更新中。

如果我落后于软件包更新，我将对apt-get install一些大的（可能是 php、apache2 等）进行更新，以便我可以将它们包含在内并检查任何问题，然后apt-get upgrade在我完成后。

Answer 2

我用apt list --upgradable.
下一个选择是apt-get --simulate upgrade。（基于@EightBitTony）
以下是不同选项的输出（希望对某人有所帮助）：

me@machine:~$ 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.

me@machine:~$ 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])

me@machine:~$ 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?

me@machine:~$ 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.

me@machine:~$ 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.

Answer 3

列出要升级的软件包及其版本：

$ 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.

然后，您可以选择要升级的内容：

$ 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]
...

如果删除了任何旧的依赖项，则可以运行apt-get autoremove，并且如您所见，将提示安装任何新的依赖项。该--only-upgrade标志不是必需的，但如果您想确保不会意外安装新软件包而不是升级现有软件包，那就很好了，即您有一个这样的时刻并且不小心输入了错误的软件包：

$ 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.