Ubuntu can not log dead loop problem solved
Some time ago in the computer installed Win7+ubuntu dual system, and then set up in Ubuntu Java Development environment, install JDK, Tomcat, Eclipse, MySQL, and other configuration environment variables, and so on after all finished Ubuntu unexpectedly restart, Then to the landing page, enter the user name, password landing does not go in, prompted a flash of information, and so has been dead cycle in the landing, do not know what the reason, so Google a bit, finally found the reason, is the JDK environment variable configuration of the problem,
Here are the solutions:
In the login screen, press alt+ctrl+f2 into the Tty2,
Because the environment variable is not set, the command at this time has to be fully path
For example, LS to play/bin/ls, to edit the/etc/environment file,
To have root permission, anyway my computer is, so to use the following command:
Edit the/etc/environment file and move the cursor to the row you want to delete.
Press DD (two times D) will be deleted, and then enter ": Wq" (excluding double quotes) Save Exit VI, and then exit Exit Tty2.
Finally login again, ok!