Enter the correct user name and password in Ubuntu and then repeat the logon interface (environment variable)

I did not accidentally install eclipse.

Enter the correct user name and password for Ubuntu and then repeat the logon page.

Question:
This is a question I found when I encountered this problem. I just referred to the operation in this article.

Problem:
The logon interface loops. But cannot enter the desktop.

Cause:
I am playing android. Install JDK 6. When setting the path, the same path is added to the following three files:/etc/profile,/etc/environment ,~ /. Bachrc

Explanation:
Because the permissions of the three files are different, the interface may be restored before the interface can be accessed.

Solution:
CTRL + ALT + F1 ~ F6, you can enter the command line mode, which is tty1 ~ Tty6.
Note: CTRL + ALT + F7 is the window mode.

Use the user name and password.

Sudo =/usr/bin/sudo
Vi =/usr/bin/Bi
Remove the/home/sjjz/android-sdk-linux_86/tools path added to the path in the three files
Whereis =/usr/bin/whereis
Cat = // bincat
MV =/bin/mv
Ls =/bin/ls
Bash =/bin/bash

Restart:
/Usr/bin/sudo/sbin/reboot