Set exit code to 1 in case at least one of the input files

could not be opened.

sbin/md5/md5.1

@@ -67,6 +67,10 @@ Run a built-in time trial.
 .It Fl x
 Run a built-in test script.
 .El
+.Sh DIAGNOSTICS
+The
+.Nm
+program exits 0 on success, and 1 if at least one of the input files could not be read.
 .Sh SEE ALSO
 .Xr cksum 1
 .Rs

sbin/md5/md5.c

@@ -62,7 +62,9 @@ main(int argc, char *argv[])
 	int     ch;
 	char   *p;
 	char	buf[33];
+	int     failed;
 
+	failed = 0;
 	while ((ch = getopt(argc, argv, "pqrs:tx")) != -1)
 		switch (ch) {
 		case 'p':
@@ -93,19 +95,24 @@ main(int argc, char *argv[])
 	if (*argv) {
 		do {
 			p = MD5File(*argv, buf);
-			if (!p)
+			if (!p) {
 				warn("%s", *argv);
-			else
+				failed++;
+			} else {
 				if (qflag)
 					printf("%s\n", p);
 				else if (rflag)
 					printf("%s %s\n", p, *argv);
 				else
 					printf("MD5 (%s) = %s\n", *argv, p);
+			}
 		} while (*++argv);
 	} else if (!sflag && (optind == 1 || qflag || rflag))
 		MDFilter(0);
 
+	if (failed != 0)
+		return (1);
+ 
 	return (0);
 }
 /*