diff --git a/docs/mm.1 b/docs/mm.1
index e84ac66..2244588 100644
--- a/docs/mm.1
+++ b/docs/mm.1
@@ -56,7 +56,7 @@ writing to that particular output, and if there are more outputs specified,
 continues, eventually exiting unsuccessfully.
 .PP
 On error mm prints a diagnostic message and exits with the appropriate
-sysexits.h(3) status. 
+sysexits.h(3) status.
 
 .SH BUGS
 
diff --git a/src/mm.c b/src/mm.c
index 5e81f7f..ff62148 100644
--- a/src/mm.c
+++ b/src/mm.c
@@ -132,53 +132,57 @@ int main(int argc, char *argv[]){
 
 	k = 0;
 
-	while((c = getopt(argc, argv, "aehi:no:u")) != -1)
-		switch(c){
-		case 'a': /* "rb+" -> "ab" */
-			files[1].mode[0] = 'a';
-			files[1].mode[2] = '\0';
-			break;
-		case 'e':
-			if(Files_append(&files[1], stderr, stderr_name) != NULL)
+	if(argc > 0)
+		program_name = argv[0];
+
+	if(argc > 1)
+		while((c = getopt(argc, argv, "aehi:no:u")) != -1)
+			switch(c){
+			case 'a': /* "rb+" -> "ab" */
+				files[1].mode[0] = 'a';
+				files[1].mode[2] = '\0';
 				break;
-			retval = oserr(argv[0], "-e");
-			terminate;
-		case 'i':
-			if((strcmp(optarg, "-") == 0 && Files_append(&files[0],
-						stdin, stdin_name) != NULL)
-					|| Files_open(&files[0], optarg) != NULL)
-				break;
-			retval = oserr(argv[0], optarg);
-			terminate;
-		case 'o':
-			if((strcmp(optarg, "-") == 0 && Files_append(&files[1],
-						stdout, stdout_name) != NULL)
-					|| Files_open(&files[1], optarg) != NULL)
-				break;
-			/* does not exist, so try to create it */
-			if(errno == ENOENT){
-				files[1].mode = wharsh;
-				if(Files_open(&files[1], optarg) != NULL){
-					files[1].mode = fmode[1];
+			case 'e':
+				if(Files_append(&files[1], stderr, stderr_name) != NULL)
 					break;
+				retval = oserr(argv[0], "-e");
+				terminate;
+			case 'i':
+				if((strcmp(optarg, "-") == 0 && Files_append(&files[0],
+							stdin, stdin_name) != NULL)
+						|| Files_open(&files[0], optarg) != NULL)
+					break;
+				retval = oserr(argv[0], optarg);
+				terminate;
+			case 'o':
+				if((strcmp(optarg, "-") == 0 && Files_append(&files[1],
+							stdout, stdout_name) != NULL)
+						|| Files_open(&files[1], optarg) != NULL)
+					break;
+				/* does not exist, so try to create it */
+				if(errno == ENOENT){
+					files[1].mode = wharsh;
+					if(Files_open(&files[1], optarg) != NULL){
+						files[1].mode = fmode[1];
+						break;
+					}
 				}
-			}
-			retval = oserr(argv[0], optarg);
-			terminate;
-		case 'n':
-			if(signal(SIGINT, SIG_IGN) != SIG_ERR)
+				retval = oserr(argv[0], optarg);
+				terminate;
+			case 'n':
+				if(signal(SIGINT, SIG_IGN) != SIG_ERR)
+					break;
+				retval = oserr(argv[0], "-n");
+				terminate;
+			case 'u':
+				k = 1;
 				break;
-			retval = oserr(argv[0], "-n");
-			terminate;
-		case 'u':
-			k = 1;
-			break;
-		default:
-			fprintf(stderr, "Usage: %s (-aenu) (-i [input])..."
-				" (-o [output])...\n", argv[0]);
-			retval = EX_USAGE;
-			terminate;
-		}
+			default:
+				fprintf(stderr, "Usage: %s (-aenu) (-i [input])..."
+					" (-o [output])...\n", argv[0]);
+				retval = EX_USAGE;
+				terminate;
+			}
 
 	files[0].s += files[0].s == 0;
 	files[1].s += files[1].s == 0;
@@ -202,6 +206,8 @@ int main(int argc, char *argv[]){
 				if(putc(c, files[1].files[j]) == EOF){
 					/* notebook's full */
 					retval = EX_IOERR;
+					fprintf(stderr, "%s: %s: %s\n",
+						program_name, files[1].names[j], strerror(errno));
 					if(fclose(files[1].files[j]) == EOF)
 						fprintf(stderr, "%s: %s: %s\n",
 							program_name, files[1].names[j], strerror(errno));