This is a WWW interface for CVS Repositories. You can browse the file hierarchy by picking directories (which have slashes after them, e.g., src/). If you pick a file, you will see the revision history for that file. Selecting a revision number will download that revision of the file. There is a link at each revision to display diffs between that revision and the previous one, and a form at the bottom of the page that allows you to display diffs between arbitrary revisions.
$ cvs -d email@example.com:/cvs checkout -P ports/net/libtorrent ports/net/rtorrent
$ cvs -q up -Pd -A
$ cvs diff -u ports/net/libtorrent/Makefile > /tmp/patch
E-mail diffs to: namn at berkeley dot edu
If you would like to use this CGI script on your own web server and CVS tree, download the latest version from <URL:https://www.FreeBSD.org/projects/cvsweb.html>.