need help - C program on redirection

[KiranJyothi]

Hello All,

In whotofile.c, we can see that we are redirecting the output of who to a file.


In pipe.c, we see that we are redirecting the o/p of first command as the input to the next command.

I want to write a program without using dup or dup2 to redirect the output of who as the input of sort.

Can anyone please help me with this?

Thanks in advance.

-KiranJyothi

[gpraghuram]

I havent seen the code fully----
I am answering for below part
I want to write a program without using dup or dup2 to redirect the output of who as the input of sort.

Logic for this is
1)First open a file using open system call
2)As it is opened successfully what you do is dup the file descriptor
3)Then use dup2 to swap the file descriptor to the stdout's descriptor
4)Now whatever you write to stdout will be part of the file
5)As you are done again call dup2 to swap the descriptors properly
6)close the file descriptor

Raghuram