I know that dup, dup2, dup3 "create a copy of the file descriptor oldfd"(from man pages). However I can't digest it.

As I know file descriptors are just numbers to keep track of file locations and their direction(input/output). Wouldn't it be easier to just

fd=fd2;

Whenever we want to duplicate a file descriptor?

And something else..

dup() uses the lowest-numbered unused descriptor for the new descriptor.

Does that mean that it can also take as value stdin, stdout or stderr if we assume that we have close()-ed one of those?

c pipe dup2 dup
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