-#include <sys/types.h> /* predefined types */
-#include <sys/stat.h> /* stat deinitiions */
-#include <unistd.h> /* include unix standard library */
-/* */
-#include <stdio.h> /* include standard I/O library */
-#include <stdlib.h> /* include standard library */
-#include <string.h> /* include string library */
-#include <wait.h> /* include wait call */
-#include <fcntl.h>
-#include <assert.h>
-#include <time.h>
+#include <sys/types.h> /* primitive system data types */
+#include <sys/stat.h> /* file characteristics constants and functions */
+#include <unistd.h> /* unix standard library */
+#include <stdio.h> /* standard I/O library */
+#include <stdlib.h> /* C standard library */
+#include <string.h> /* C strings library */
+#include <wait.h> /* process termination constants and functions */
+#include <fcntl.h> /* file control functions */
+#include <assert.h> /* C assertion functions */
+#include <time.h> /* date and time constants, types and functions */