ubuntu进入recover 模式的问题~细节会误导人

winston

今日因为不小心，把ubuntu 14.04的默认用户改换了分组，结果导致危机：所有的重要命令都无法使用，没有sudo权限。想修改自己也做不到。

找了一下网络上的资料，就是要重启进入Recover模式，进行修复。但是根据要求，我怎么也进不了修复模式，连启动菜单都看不到。
比如这篇：
http://www.psychocats.net/ubuntu/fixsudo
Booting into recovery modeSince fixing sudo involves editing system files, and you would otherwise need sudo to do so, you'll have to boot into recovery mode to gain root (system-wide) access in order to repair sudo.

If you have a single-boot (Ubuntu is the only operating system on your computer), to get the boot menu to show, you have to hold down the Shift key during bootup.

开机长按shift键盘，这个是重点，长按shift键，然后就会进入引导菜单

http://jingyan.baidu.com/article/f3ad7d0fff331509c3345bfb.html

后来才发现被误导了：

Don't hold it down. Tap it repeatedly, I still don't know why everyone says hold it down. Also start as soon as the bios logo, some bioses (bios's? I just woke up and my English is lacking atm) will think you have a stuck key and disable it, I've only seen this one, but thought it might be worth mentioning.

http://ubuntuforums.org/showthread.php?t=1975550
不要按住，要重复按键。尝试了一下，果然如此。


进入Recover模式，进行修复就可以了。作为开发用机，实际上不用这么麻烦，一开始就给root帐号设置个密码，以防万一就好了。
sudo passwd root
这样在出问题的时候，直接运行su命令一下，进入root帐号进行修复。