p1.c

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <time.h>

int
main(int argc, char *argv[])
{
    time_t t = time(NULL);
    struct tm tm = *localtime(&t);
    printf("%d-%02d-%02d %02d:%02d:%02d\n", tm.tm_year + 1900, tm.tm_mon + 1, tm.tm_mday, tm.tm_hour, tm.tm_min, tm.tm_sec);
    printf("hello world (pid:%d)\n", (int) getpid());
    int rc = fork();
    if (rc < 0) {
        // fork failed; exit
        fprintf(stderr, "fork failed\n");
        exit(1);
    } else if (rc == 0) {
        // child (new process)
        printf("hello, I am child (pid:%d)\n", (int) getpid());
    } else {
        // parent goes down this path (original process)
        printf("hello, I am parent of %d (pid:%d)\n",
	       rc, (int) getpid());
    }
    return 0;
}