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

main()
{ int pid;
  printf("Single\n");
  pid = fork();
  if (pid < 0)
  { perror("fork failed");
    exit(-1);
  }
  else if (pid == 0)    /* child */
  { printf("  Child Process\n");
    printf("  Executing ls using execl ...\n");

    execl("/bin/ls", "ls", "-lt", (char *) 0);

    /* If execl returns, the call has failed */
    perror("execl failed to run ls");
    exit(-1);
  }
  else                  /* parent */
  { wait( (int *)0 );   /* wait to avoid child zombie  */
    printf("Parent Process\n");
    printf("--my child has completed the ls\n");
    exit(0);
  }
}