diff --git a/walk/walk.c b/walk/walk.c
index 10dbde7..6c9a23b 100644
--- a/walk/walk.c
+++ b/walk/walk.c
@@ -34,8 +34,9 @@
  */
 
 #include <errno.h> /* errno */
+#include <limits.h> /* UINT_MAX */
 #include <stdio.h> /* fprintf(3), perror(3), stderr, stdout */
-#include <stdlib.h> /* free(3), realloc(3) */
+#include <stdlib.h> /* free(3), realloc(3), strtol(3) */
 #include <string.h> /* stpcpy(3), strcmp(3), strerror(3), strlen(3) */
 #if !defined EX_OK || !defined EX_INVALID || !defined EX_OSERR \
 		 || !defined EX_USAGE
@@ -65,7 +66,7 @@ fnprint(char *fn){
  * contains (but not the name of the directory itself).
  * Returns something other than EX_OK with errno set if an error occurs. */
 static int
-walk(char *dirname, char *argv0){
+walk(char *dirname, unsigned int levels, char *argv0){
 	DIR *dir;
 	struct dirent *f;
 	struct { size_t a; char *s; } filename = { 0, NULL };
@@ -92,11 +93,11 @@ walk(char *dirname, char *argv0){
 			filename.s = np;
 		}
 		stpcpy(stpcpy(stpcpy(filename.s, dirname), "/"), f->d_name);
-		/* TODO(bbaren@google.com): Emulate Plan 9's cleanname(3). */
 		/* Walk the file if we can successfully open it as a
 		 * directory. */
-		if(f->d_type == DT_DIR || f->d_type == DT_UNKNOWN){
-			if((retval = walk(filename.s, argv0)) != EX_OK){
+		if((f->d_type == DT_DIR || f->d_type == DT_UNKNOWN) && levels != 0){
+			if((retval = walk(filename.s, levels == -1 ? -1 : levels - 1,
+					argv0)) != EX_OK){
 				if(retval == EX_OSERR){
 					free(filename.s);
 					return retval;
@@ -119,18 +120,28 @@ walk(char *dirname, char *argv0){
 int main(int argc, char *argv[]){
 	char *argv0;
 	int c;
+	int levels;
 	int retval;
 
 	argv0 = argv[0] == NULL ? program_name : argv[0];
+	levels = -1; /* no limit */
 	terminator = asv_terminator;
 
 	if(argc > 0){
 		while((c = getopt(argc, argv, "0d:l:n")) != -1)
 			switch(c){
 			case '0': terminator = nul_terminator; break;
-			case 'd': terminator = optarg; break;
-			case 'l': /* TODO */ break;
 			case 'n': terminator = newl_terminator; break;
+			case 'd': terminator = optarg; break;
+			case 'l': {
+				long l;
+
+				if((l = strtol(optarg, &optarg, 0) - 1) >= 1 && l <= INT_MAX
+						&& *optarg != '\0'){
+					levels = l;
+					break;
+				}
+			}
 			default:
 				fprintf(stderr,
 					"Usage: %s (-0n)"
@@ -147,7 +158,7 @@ int main(int argc, char *argv[]){
 		argv = dot;
 
 	while(*argv != NULL)
-		if((retval = walk(*(argv++), argv0)) != EX_OK)
+		if((retval = walk(*(argv++), levels, argv0)) != EX_OK)
 			switch(retval){
 			case EX_OSERR: perror(argv0); return retval;
 			case EX_NOINPUT: