You get this error when you try to run the command without root privileges. Try "sudo restart squid" instead.
But I think you will run into a real bug then: https://bugs.launchpad.net/ubuntu/+source/squid/+bug/573853 -- Error on restarting squid https://bugs.launchpad.net/bugs/590173 You received this bug notification because you are a member of Ubuntu Server Team, which is subscribed to squid in ubuntu. -- Ubuntu-server-bugs mailing list Ubuntu-server-bugs@lists.ubuntu.com Modify settings or unsubscribe at: https://lists.ubuntu.com/mailman/listinfo/ubuntu-server-bugs
