Index: nice.c
===================================================================
RCS file: /home/ncvs/src/usr.bin/nice/nice.c,v
retrieving revision 1.4.2.1
diff -u -r1.4.2.1 nice.c
--- nice.c	18 Jun 2002 08:40:28 -0000	1.4.2.1
+++ nice.c	21 Jul 2005 13:19:31 -0000
@@ -70,6 +70,7 @@
 {
 	long niceness = DEFNICE;
 	int ch;
+	int what = PRIO_PROCESS;
 	char *ep;
 
 	/* Obsolescent syntax: -number, --number */
@@ -78,8 +79,10 @@
 		if (asprintf(&argv[1], "-n%s", argv[1] + 1) < 0)
 			err(1, "asprintf");
 
-	while ((ch = getopt(argc, argv, "n:")) != -1) {
+	while ((ch = getopt(argc, argv, "d:n:")) != -1) {
 		switch (ch) {
+		case 'd':	/* disk I/O priority */
+			what = 4; /* PRIO_DISK */
 		case 'n':
 			errno = 0;
 			niceness = strtol(optarg, &ep, 10);
@@ -98,10 +101,11 @@
 		usage();
 
 	errno = 0;
+	if (what == PRIO_PROCESS)
 	niceness += getpriority(PRIO_PROCESS, 0);
 	if (errno)
 		warn("getpriority");
-	else if (setpriority(PRIO_PROCESS, 0, (int)niceness))
+	else if (setpriority(what, 0, (int)niceness))
 		warn("setpriority");
 	execvp(*argv, argv);
 	err(errno == ENOENT ? 127 : 126, "%s", *argv);