#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <sys/wait.h>
#include <string.h>

struct {
    char    *abbrev;
    char    *fullname;
} days[] = {
    "Sun",  "Sunday",
    "Mon",  "Monday",
    "Tue",  "Tuesday",
    "Wed",  "Wednesday",
    "Thu",  "Thursday",
    "Fri",  "Friday",
    "Sat",  "Saturday",
    0,      0
};

int main(void) {
    pid_t pid;
    int pfd[2];
    int i, status;
    char line[64];
    
     /* Create a pipe.*/
    if (pipe(pfd) < 0) {
        perror("pipe");
        exit(1);
    }

    /* Create a child process.*/
    if ((pid = fork()) < 0) {
        perror("fork");
        exit(1);
    }

    /* The child process executes "date". */
    if (pid == 0) {
        /* Attach standard output to the pipe. */
        dup2(pfd[1], 1);
        close(pfd[0]);

        execl("/bin/date", "date", (char *) 0);
        perror("exec");
        _exit(127);
    }

    /* We will not be writing to the pipe. */
    close(pfd[1]);

    /* Read the output of "date". */
    if (read(pfd[0], line, 3) < 0) {
        perror("read");
        exit(1);
    }

    /* For each day, see if it matches the output
     * from the date command. */
    printf("I am the pipe version !!!\n");
    for (i=0; days[i].abbrev != NULL; i++) {
        if (strncmp(line, days[i].abbrev, 3) == 0)
            printf("Today is %s.\n", days[i].fullname);
        else
            printf("Today is not %s.\n", days[i].fullname);
    }

    /* Close the pipe and wait for the child
     * to exit.  */
    close(pfd[0]);
/*    waitpid(pid, &status, 0);*/
     wait(&status);

    /* Exit with a status of 0, indicating that
     * everything went fine. */
    exit(0);
}