I know what happened. Somehow, the content of every single file in my packages directory was replaced by this by the firewall at my school when I forgot to log in before checking for updates:
<HTML><HEAD><META HTTP-EQUIV="refresh" CONTENT="0;URL=https://192.168.76.1:4100/fw_user_login.html?redirect=http://extras.ubuntu.com/ubuntu/dists/precise/InRelease"><meta http-equiv="PRAGMA" content="no-cache"><meta http-equiv="Cache-Control" content="no-cache"><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"></HEAD><BODY><b>You must login before accessing this site.</b><p>Your browser should be redirected to the login page shortly, or you can navigate directly there by selecting the link below:</p><a href="https://192.168.76.1:4100/fw_user_login.html?redirect=http://extras.ubuntu.com/ubuntu/dists/precise/InRelease">Firewall Login Dialog</a></BODY></HTML>
There are 18 files that contain nothing but that now.
I know what happened. Somehow, the content of every single file in my packages directory was replaced by this by the firewall at my school when I forgot to log in before checking for updates:
<HTML><HEAD><META HTTP-EQUIV= "refresh" CONTENT="0;URL=https:/ /192.168. 76.1:4100/ fw_user_ login.html? redirect= http:// extras. ubuntu. com/ubuntu/ dists/precise/ InRelease"><meta http-equiv="PRAGMA" content= "no-cache" ><meta http-equiv= "Cache- Control" content= "no-cache" ><meta http-equiv= "Content- Type" content="text/html; charset= UTF-8"> </HEAD> <BODY>< b>You must login before accessing this site.</b><p>Your browser should be redirected to the login page shortly, or you can navigate directly there by selecting the link below:</p><a href="https:/ /192.168. 76.1:4100/ fw_user_ login.html? redirect= http:// extras. ubuntu. com/ubuntu/ dists/precise/ InRelease">Firewall Login Dialog< /a></BODY> </HTML>
There are 18 files that contain nothing but that now.