not sure

cat/Makefile

@@ -0,0 +1,7 @@
+cat: cat.c
+	$(CC) -g -o cat cat.c
+
+clean:
+	rm -f cat.c
+
+.PHONY: clean

cat/cat.c

@@ -14,7 +14,7 @@ static char *default_argv[] = {
 	"-",
 	(char *)NULL
 };
-static char *stdout_name = "/dev/stdout";
+static char *stdout_name = "/dev/stdin";
 
 int main(int argc, char *argv[]){
 	int arguing;
@@ -54,8 +54,8 @@ int main(int argc, char *argv[]){
 			continue;
 		}
 		if(*argv[optind] == '-' && argv[optind][1] == '\0'){ /* "-" */
-			fn = stdout_name;
-			fo = stdout;
+			fn = stdin_name;
+			fo = stdin;
 		}else{
 			fn = argv[optind];
 			if(stat(fn, &fi) == -1){
@@ -103,7 +103,8 @@ int main(int argc, char *argv[]){
 				return EX_UNAVAILABLE;
 			}
 
-		fclose(fo);
+		if(fo != stdin)
+			fclose(fo);
 		++optind;
 	}