ubuntu apt-get update失败
出现错误1处理：
E:Could not get lock /var/lib/apt/lists/lock - open (11: Resource temporarily unavailable)
出现这个问题的原因可能是有另外一个程序正在运行，导致资源被锁不可用。而导致资源被锁的原因，可能是上次安装时没正常完成，而导致出现此状况。
解决方法：把 /var/lib/apt/lists 中的文件全部删掉
输入以下命令:
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock
之后再安装想装的包，即可解决
出现错误2处理：
E: Some index files failed to download. They have been ignored, or old ones used instead.
解决方法：
To upgrade a really old Ubuntu release, we first need to edit our sources.
list and change all(xx.)archive.ubuntu.com to old-releases.ubuntu.com.
sudo emacs /etc/apt/sources.list
sudo apt-get update