Squid cache purging by URL pattern

Sometime squid play cruel jokes on you, especially with fast-changing debian repositories.

While this Squid WIKI article claims this to be impossible, there is a workaround that usually helps:

for U in $(grep "GET http://deb.foo.bar/" /var/log/squid3/access.log |awk '{print $7}' |sort |uniq) ; do squidclient -r -s $U ; done