userspace/piper.c


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#include <stdio.h>
#include "newcalls.h"

extern **environ;

int main()
{
    int fds[2];
    _pipe(fds);

    int pid=_fork();

    if(pid)
    {
	_close(fds[1]);
	_dup2(fds[0],0); // replace stdin with the read-end of pipe
	char *args[]={"grep",NULL};
	_execve("/bin/grep",args,environ);
    }
    else
    {
	_close(fds[0]);
	_dup2(fds[1],1); // replace stdout with the write-end of our pipe
	char *args[]={"cat","hello.txt",0};
	_execve("/bin/cat",args,environ);
    }
}