Learn ju-jitsu, taekwondo, or another martial art which trains you to defend yourself against multiple attackers. While these ferals may appear fearsome in packs, they are actually terrible fighters in a one-on-one scenario.
I am that huckleberry, and I have been jumped by 5 Amish on the street, and I did pretty damn good to keep myself alive and get the f out of there.
I was very amused that the one guy I did manage to muss up started to spread a story that the old white guy was the one who jumped all of them.
Canes are very good, but most canes are too light. Find a piece of wood that suits and Dremel your own. Interesting in a defensive sense, watch how the democracy protestors in China use umbrellas. Also, I know from experience a tough briefcase full of heavy items is devastating if you have the delts and tris to swing it, a real bonebreaker, as well as a shield.
Attitude is everything. I once had to get a POed tomcat out of a dark attic by grabbing it with my bare hands, I'd say the commitment adrenaline and focus is similar. But nothing they do will hurt, live to see tomorrow, THEN you'll hurt.