ubuntu 14.04 升级到 16.04 问题总结

1. 需要的依赖关系未安装

The required dependency 'apt (>= 1.0.1ubuntu2.13)' is not installed.
http://forum.ubuntu.org.cn/viewtopic.php?t=479718

尝试：

1)保持软件源指向 14.04(trusty) 不变
2) sudo apt-get update && sudo apt-get upgrade
此时 apt 应已升级到 1.0.1ubuntu2.13参考 http://packages.ubuntu.com/trusty/apt

3)sudo update-manager -d

2.How to select option in “Configuration grub-pc” menu

https://askubuntu.com/questions/384388/how-to-select-option-in-configuration-grub-pc-menu

1)Use [tab] to switch between options, use [spacebar] to select.
2) Select continue without installing grub,and then update your grub by running below command,
sudo update-grub

3.What do I select for “GRUB install devices” after an update?

https://askubuntu.com/questions/23418/what-do-i-select-for-grub-install-devices-after-an-update

In your case, the correct selection is /dev/sda, the first one. It's the first and only hard disk in your system, whereas /dev/sda1 is a partition on that hard disk. You can install grub on a partition, but it's a "BAD idea".

If you had multiple hard drives and partitions, first find out where your root partition is:
lsblk
(See also: How do I find out what hard disks are in the system?)
You can then install grub on that hard drive. Look for devices labeled "disk" (e.g. "sda", meaning /dev/sda) to install grub into the master boot record (every physical disk device has only one MBR, no matter the partitions).

4.GRUB默认启动顺序修改

ubuntu的/boot/grub目录下，该目录下有个文件grub.cfg，就是设置默认启动的文件。

1)修改权限， sudo chmod w ./grub.cfg
2) grub.cfg里 set default = "0" 将0改为你电脑windows系统的index

使用 apt 命令的时候会报这个错

Ignoring file '50unattended-upgrades.ucf-dist' in directory '/etc/apt/apt.conf.d/' as it has an invalid filename extension

解决办法原文参照：https://askubuntu.com/questions/829370/n-ignoring-file-50unattended-upgrades-ucf-dist-in-directory-etc-apt-apt-con/829585

简而言之： 删掉报错的文件就行了。。。。

sudo rm /etc/apt/apt.conf.d/50unattended-upgrades.ucf-dist