I was riding my bike and rear brake fell apart. As a result I lost the short wire of the cantilever brake, or at least that what it seems to be called. Where can I buy that short cable please ? Here is the same piece of the front brake:
Amazon or your local bike shop.
Here's a double ended (you can cut into one or two depending on length you need) on Amazon: BRAKE PART STRADDLE CABLE ACTION ROAD 2-ENDS 110MM.
I know an answer has been selected, but I wanted to post this here for future reference.
First - the common name for that type part is a "straddle cable" or a "link wire" depending on the variations or the manufacturer.
Second - my primary source (after my LBS) for less-common parts, especially parts for older bikes or the bike-shaped objects the neighborhood kids want me to fix is Loose Screws.
Here is their Straddle Cable page.