问题：
default@default:~$ sudo apt-get install openssh-server
Reading package lists... Error!
E: Malformed Description-md5 line; doesn't have the required length (32 != 117)
E: Unable to parse package file /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_raring_main_binary-i386_Packages (1)
E: Problem opening /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_raring_universe_binary-i386_Packages
E: The package lists or status file could not be parsed or opened.
解决方法：
sudo apt-get clean
cd /var/lib/apt
sudo mv lists lists.old
sudo mkdir -p lists/partial
sudo apt-get clean
sudo apt-get update