http://www.di.uevora.pt/~lmr/syscalls.html In that reference about system calls, appears a function called dup(). It is said that it duplicates channels. Then my question is, what is a channel?
What is a channel?
system calls
The meaning of the term channel is explained earlier on the same page under the heading File Structure Related System Calls: A channel is a connection between a process and a file that appears to the process as an unformatted stream of bytesAs in Unix Everything is a file, this includes file descriptors to regular files, but also different kinds of sockets, pipes, FIFOs etc.