diff --git a/src/rt/shell/fs/search.ts b/src/rt/shell/fs/search.ts
new file mode 100644
index 0000000..d032d81
--- /dev/null
+++ b/src/rt/shell/fs/search.ts
@@ -0,0 +1,33 @@
+interface Search {
+	binary: <T>(list: T[], find: T) => T | undefined,
+	linear: <T>(list: T[], find: T) => T | undefined,
+}
+const search = {} as Search
+
+search.binary = function(list, find) {
+	list.sort()
+	let start = 0
+	let end = list.length-1
+	while (start<=end) {
+		const median = (start+end)>>1
+		if (list[median] === find) {
+			return find
+		} else if (list[median]<find) {
+			start = median+1
+		} else {
+			end = median-1
+		}
+	}
+	return
+}
+
+search.linear = function(list, find) {
+	for (const item of list) {
+		if (item === find) {
+			return item
+		}
+	}
+	return
+}
+
+export default search
\ No newline at end of file