#include <stdio.h>
#include <unistd.h>
#include <sys/wait.h>

int main(void)
{
    int pip[2];
    
    pipe(pip);
    
    if(!fork())
    {
        // make pip[1] a stdout
        dup2(pip[1], 1);
        close(pip[1]); // close the unneeded fd
        
        close(pip[0]); // close unneeded fd (reading part of pipe)
        
        execl("/bin/sh", "sh", "-c", "echo x", NULL);
        _exit(-1);
    }
    
    close(pip[1]); // close unneeded fd (writing part of pipe)
    
    FILE*fp = fdopen(pip[0], "rt");
    char Buf[512];
    fgets(Buf,sizeof Buf,fp);
    fclose(fp);
    
    printf("Got %s\n", Buf);
    while(wait() > 0);
    return 0;
}