Is it possible to redirect input/output from fd other then stdin,stdout,stderr

Question

I'm aware of piping in linux shell (i have a very basic knowledge of it).

Lets say i have an executable that i know reads from a specific file (or from a socket), is it possible to redirect the output/input of this file using shell piping, like it is with stdin/out/err?

Thanks

Answer 1

Yes, absolutely. One way is to call dup() or dup2() and close() the original file. But of course, you'll need source code to modify the original program.