修复Ubuntu Terminal的彩色显示

Ubuntu终端下的输出都变成黑白的，并且常用的ll命令提示command not found.

造成这种情况的原因是home目录下的.bashrc文件丢失。将正确的文件copy回来即可。

sudo cp /etc/skel/.bashrc ./

是用这个文件的原因是：

Basically, the /etc/bash.bashrc file is used for system-wide (applies to all users) interactive bash shells. The /etc/skel/.bashrc is a 'skeleton' file that gets copied to the home directory of a user upon creation.

来源在这里。