feat: add fs tools (#59)

tools/fs_ls.sh

@@ -0,0 +1,14 @@
+#!/usr/bin/env bash
+set -e
+
+# @describe List all files and directories at the specified path.
+
+# @env FS_BASE_DIR=. The base dir
+# @option --path! The path of the directory to list
+
+main() {
+    path="$FS_BASE_DIR/$argc_path"
+    ls -1 "$path"
+}
+
+eval "$(argc --argc-eval "$0" "$@")"