Can I ride my bike home if the clutch cable breaks?
Yes, you can
Making it home without a clutch is something you can do. Just remember that no matter what you do, you cannot stop quickly without a clutch. The bike is in gear, and you can't use the bike's brakes to their fullest. Stopping for lights or stop signs could become a bit of an adventure. However, there are some times where the safest thing to do is to keep riding, such as if you happen to be in the middle of a busy freeway/expressway.
Of course, the clutch is there for a reason, and shifting without it will wear your transmission out more quickly. In short, this should only be used in an emergency. Learn how, then hope you don't have to.
The best thing to do is get a spare cable and zip-tie it to the current one. Should your cable break, it is just a matter of hooking up both ends and you are on your way home.
Clutchless shifting is just a matter of matching rpm. On upshifts you have to back off the throttle for an instant as you bang the box into the next gear. Put a bit of upward pressure on the shifter before rolling off the gas; it will just snick right into place.
Downshifting is tougher, but doable. On downshifts you have to rev the engine up a bit as you drop a gear. See blipping the throttle.
First to second is going to be the hardest shift. One way to circumvent it is to let the throttle drop, shift into neutral, and then shift into second once you're at the right RPM. It's a lot smoother if you get it right, but it's pretty bad if you get it wrong. This is basically the same as double-clutching and rev-matching. It's a little difficult to get right at first, but once you get it it's a lot better than brute-shifting such a large ratio.
Coming to a stop
When coming to a stop in traffic, brake early and keep downshifting. That way you can approach the light at a very slow speed; this is likely to piss off the person behind you, but it'll sometimes provide enough time for the light to turn green so you don't have to kill the engine. Judge the traffic and local driving habits, and keep an eye on your mirrors when you do this.
You can go really slow without letting the engine die. It'll sputter, but it'll pull in first gear. You can do a rolling stop at a stop sign, if necessary, but only do it when you can see both ways. This is handy when going uphill and stopping wouldn't be good.
Don't ever stop on a steep hill. This is not just an inconvenience, it's an impossibility - you can't get the bike moving. You'll have to wheel the bike around and ride back down. Can be embarassing.
When parking the bike, try to find neutral as you're swinging in, so you can maneuver where you want to be and then hit the kill switch. Finding neutral is also a chore - you'll want to do it before you're at a crawl.
Stopping and starting
You have two choices if you have to stop on the street:
1. Shift into neutral when you approach a stop, leaving the bike running. It's easiest to go all the way down to first, then go back up to neutral. Then, duck walk the bike at idle to get it moving, shift into first gear, and ride off. Keep the revs at idle when you click it into first; you'll then be able to accelerate.
2. Get as slow as you can in first gear, then hit the kill switch. Alternately, just slowly brake until the engine dies. When you're ready to take off, your engine won't be running. This is an inconvenience, but a minor one. To start rolling:
Choose your route
This should be obvious, but if you are caught in this situation, try to stick to back streets and places without traffic and traffic lights, if you can. It's also best to avoid stopping uphill, as this can be an exercise in frustration.