Ubuntu修改用户UID为0后无法识别root和用户账号解决办法

&＃160; &＃160; &＃160; &＃160;看鸟哥私房菜时讲到多个用户可以有相同的UID，且如果将用户UID改成0后则用户拥有和root一样的权限，于是我试验了一下，修改/etc/passwd文件，将我登录的用户yhl的UID改成0（和root的UID相同），这一改就出问题了，当我在终端退出登录再重新用root/yhl账号登录的时候系统提示识别不了用户名，而且我的yhl账号也并没有修改/etc/passwd的权限，重启Ubuntu时桌面更是连登录账号都不显示了。

&＃160; &＃160; &＃160;上网查了下解决办法，如下

ask ubuntu的方案（From Thomas Ward）

Without booting to a LiveUSB or LiveCD/DVD, we can actually borrow some of the steps from this answer on resetting a lost password to get to a recovery console, and then make changes to the system and reboot afterwards.


To summarize the steps (everything from 1 to 4 is from the other question; 5 and 6 are the different steps to do):


(1) Boot up the system, and after you see the BIOS screen press and hold "Shift" - you&＃39;ll get the GRUB prompt.


(2) Use the &＃39;recovery mode&＃39; option for your kernel - if it doesn&＃39;t show up it&＃39;s probably under the section for "Other Ubuntu versions" or one of the other items on Grub.


(3) Once in recovery mode, select the &＃39;root&＃39; option by using the down arrow on your keyboard, and then hit Enter. You&＃39;ll end up with a command line prompt for the root user.


(4) Remount your system as read/write with this command: mount -o remount,rw /


(5) Edit your /etc/passwd file with nano (use this command: nano /etc/passwd). Once you&＃39;ve edited the specific line for your user and reset it to 1000 for the UID and GID, hit Ctrl+O, then hit Enter, and then Ctrl+X.


(6) You should now be at the root terminal prompt again. Reboot with shutdown -r now or reboot.


You should then be able to login again, and have fixed your blunder. Don&＃39;t go messing with your UID or GID, because setting yourself to 0 will break things and is horribly insecure and should never be done. (The 0 UID is for root, and root alone - DO NOT USE IT FOR ANY OTHER USER!)

大致步骤如下：

（1）重启Ubuntu系统，在看到BIOS时快速按下shift键，进入GRUB向导

（2）选择内核的修复模式（recovery mode）

（3）进入修复模式后选择root，即可进入root命令行输入界面

（4）键入命令：mount -o remount,rw /&＃160; &＃160; &＃160;获得读写系统的权限

（5）使用命令：vi /etc/passwd或者nano /etc/passwd编辑passwd文件，将用户账号的UID改回原来的值并保存退出

（6）重启系统，即可在桌面上再次看到可登陆用户