相关疑难解决方法(0)

我想知道为什么upgrade有时不想升级系统的某些部分，而dist-upgrade确实如此。这是运行后的示例apt-get upgrade：

apt-get upgrade：

rimmer@rimmer-Lenovo-IdeaPad-S10-2:~$ sudo apt-get upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
The following packages have been kept back:
  linux-generic linux-headers-generic linux-image-generic
0 upgraded, 0 newly installed, 0 to remove and 3 not upgraded.

与apt-get dist-upgrade：

rimmer@rimmer-Lenovo-IdeaPad-S10-2:~$ sudo apt-get dist-upgrade
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
The following NEW packages will be installed:
  linux-headers-3.0.0-13 linux-headers-3.0.0-13-generic
  linux-image-3.0.0-13-generic …

弹出这个：

然而，当我在终端中运行 apt-get 时，我得到：

    sudo apt-get dist-upgrade 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

    sudo apt-get upgrade 
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Calculating upgrade... Done
0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

这是怎么回事？为什么软件更新程序显示无法通过命令行安装更新？