diff --git a/walk/walk.c b/walk/walk.c
index af3f3e1..47b0aa2 100644
--- a/walk/walk.c
+++ b/walk/walk.c
@@ -12,57 +12,42 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#include <dirent.h> /* closedir(3), opendir(3), readdir(3), DIR */
 #include <errno.h> /* errno */
-#include <stdbool.h>
-#include <stdio.h> /* fprintf(3), stderr, stdout */
-#include <stdlib.h>
+#include <stdio.h> /* fprintf(3), perror(3), stderr, stdout */
+#include <stdlib.h> /* realloc(3) */
 #include <string.h> /* strerror(3) */
-#include <sysexits.h> /* EX_USAGE */
+#include <sysexits.h> /* EX_OSERR, EX_USAGE */
 
-#include <dirent.h>
 #include <getopt.h>
 
-static char *dot = "."; /* current directory */
+static char *dot[] = {".", NULL}; /* default (argc<2) */
 
 static char *nul_terminator = "\0";
 static char *newl_terminator = "\n";
 static char *asv_terminator = "\037"; /* ASCII UNIT_SEPARATOR */
+static char *terminator;
+
+static int
+fnprint(char *fn){
+	if(terminator == nul_terminator)
+		return fprintf(stdout, "%s%c", fn, nul_terminator[0]);
+	else
+		return fprintf(stdout, "%s%s", fn, terminator);
+}
 
 static char *argv0;
 
-// Like realloc(3), but exits the binary in an out-of-memory situation.
-static void *xrealloc(void *ptr, const size_t size)
-{
-	if (!(ptr = realloc(ptr, size))) {
-		perror("realloc");
-		exit(EXIT_FAILURE);
-	}
-	return ptr;
-}
-
-static void strcpy3(char *dest, const char *s1, const char *s2, const char *s3)
-{
-	stpcpy(stpcpy(stpcpy(dest, s1), s2), s3);
-}
-
-static void put_filename(const char *filename, bool null_terminate)
-{
-	if (null_terminate) {
-		fputs(filename, stdout);
-		fputc(0, stdout);
-	} else {
-		puts(filename);
-	}
-}
-
 // Walks the directory named dirname, printing the names of all files it
 // contains (but not the name of the directory itself). Returns 2 if dirname is
 // not a directory and 1 if another error occurs.
 static int
-walk(char *dirname, bool null_terminate){
+walk(char *dirname){
 	DIR dir;
 	struct dirent *f;
-	char *filename;
+	static struct { size_t a; size_t s; char *p; } filename = {0, 0, NULL};
+	size_t l;
+	char *np;
 	int retval;
 
 	if((dir = opendir(dirname)) == NULL){
@@ -74,43 +59,42 @@ walk(char *dirname, bool null_terminate){
 	errno = 0;
 	retval = 0;
 	while((f = readdir(dir)) != NULL){
-		if (strcmp(f->d_name, ".") == 0 || strcmp(f->d_name, "..") == 0)
+		if(strcmp(f->d_name, ".") == 0 || strcmp(f->d_name, "..") == 0)
 			continue;
-		filename = xrealloc(
-			filename, strlen(dirname) + 1 + strlen(f->d_name) + 1);
-		strcpy3(filename, dirname, "/", f->d_name);
-		// TODO(bbaren@google.com): Emulate Plan 9's cleanname(3).
-		put_filename(filename, null_terminate);
-		// Walk the file if we can successfully open it as a directory.
-		// Don't worry about it if it's not one (walk(filename) == 2).
+		if((l = strlen(dirname) + 1 + strlen(f->d_name) + 1)
+				> filename.a){
+			if((np = realloc(filename.p, l)) == NULL){
+				perror(argv0);
+				return EX_OSERR;
+			}else{
+				filename.a = l;
+				filename.p = np; /* would you look at that */
+			}
+		}
+		stpcpy(stpcpy(stpcpy(filename.p, dirname), "/"), f->d_name);
+		/* TODO(bbaren@google.com): Emulate Plan 9's cleanname(3). */
+		fnprint(filename.p);
+		/* Walk the file if we can successfully open it as a directory.
+		 * Don't worry about it if it's not one (walk(filename) == 2). */
 		if ((f->d_type == DT_DIR || f->d_type == DT_UNKNOWN)
-			&& walk(filename, null_terminate) == 1)
+				&& walk(filename.p) == 1)
 			retval = 1;
 	}
-	if (errno) {  // from readdir
-		perror(dirname);
+	if(errno != 0 || closedir(dir) != NULL){
+		fprintf(stderr, "%s: %s: %s\n",
+			argv0, dirname, strerror(errno));
 		retval = 1;
 	}
-	free(filename);
-	if (closedir(dir)) {
-		perror(dirname);
-		retval = 1;
-	}
-	return retval;
-}
 
-int usage(char *argv0){
-	fprintf(stderr, "Usage: %s (-0n) (-d [delimiter]) (-l [max levels])"
-		" (directories...)\n", argv0);
-	return EX_USAGE;
+	return retval;
 }
 
 int main(int argc, char *argv[]){
 	int c;
-	char *terminator;
 	int retval;
 
 	argv0 = argv[0];
+
 	if(argc > 0){
 		while((c = getopt(argc, argv, "0d:l:n")) != -1)
 			switch(c){
@@ -118,21 +102,25 @@ int main(int argc, char *argv[]){
 			case 'd': terminator = optarg; break;
 			case 'l': /* TODO */ break;
 			case 'n': terminator = newl_terminator; break;
-			default: return usage(argv[0]);
+			default:
+				fprintf(stderr,
+					"Usage: %s (-0n)"
+					" (-d [delimiter]) (-l [max levels])"
+					" (directories...)\n", argv[0]);
+				return EX_USAGE;
 			}
 		argv += optind;
 	}
 
 	retval = 0;
 
-	if(*argv == NULL){
-		put_filename(dot, terminator == nul_terminator);
-		retval |= walk(dot, terminator == nul_terminator);
-	}else
-		for(argv += optind; *argv != NULL; ++argv){
-			put_filename(*argv, terminator == nul_terminator);
-			retval |= walk(*argv, terminator == nul_terminator);
-		}
+	if(*argv == NULL)
+		argv = dot;
+
+	while(*argv != NULL){
+		fnprint(*argv);
+		retval |= walk(*(argv++));
+	}
 
 	return retval;
 }