A few improvements and your code will be pretty good.

The switch/case statement is useless, just put the code inside the if/then/else.

case 2 will NOT print to a file.

That 'wait' is going to crash if it ever gets run since wait demands a pointer. But more likely it'll just hang forever.

You have done absolutely no error checking anywhere at all ever here, so it could be failing anywhere without you ever knowing. Why not have redirect() return a value? After all, a user might ask for something impossible.

If you run this program from a shell, chances are your program will never see the >> and < stuff since the shell handles that for you. You'll need to make them strings, like '<<', to prevent the shell doing that.

You haven't told us what the error is, though. What is it?