touchfork.c

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

void child(void) {
  int ret;

  ret = execl("/usr/bin/touch", "touch", "test.txt", NULL);
  if (ret == -1) {
    perror("execv");
    exit (EXIT_FAILURE);
  }
}

int main(void) {
  pid_t pid = fork();

  if (pid > 0) {
    printf("I am the parent of pid=%d!\n", pid);
  } else if (!pid){
    printf("I am the baby!\n");
  } else if (pid == -1) {
    perror("fork");
  }

  if (!pid) {
    child();
  }

  return 0;
}