diff --git a/README.md b/README.md
index 07b1df8..350efb7 100644
--- a/README.md
+++ b/README.md
@@ -1,3 +1,4 @@
 # TODO:
+- [ ] split subcommands to functions
 - [ ] reorganize cmd option for storage
   - [ ] use subcommand
diff --git a/src/main.rs b/src/main.rs
index 65c5a7e..ca1b9d3 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -373,6 +373,7 @@ fn main() -> Result<()> {
                     for (k, storage) in &storages {
                         println!("{}: {}", k, storage);
                         println!("    {}", storage.mount_path(&device, &storages)?.display());
+                        // println!("{}: {}", storage.shorttypename(), storage.name()); // TODO
                     }
                 }
                 StorageCommands::Bind {
diff --git a/src/storages.rs b/src/storages.rs
index 912e632..7e3ece6 100644
--- a/src/storages.rs
+++ b/src/storages.rs
@@ -27,7 +27,25 @@ pub enum Storage {
     Online(OnlineStorage),
 }
 
-impl Storage {}
+impl Storage {
+    /// Full type name like "PhysicalStorage".
+    pub fn typename(&self) -> &str {
+        match self {
+            Self::PhysicalStorage(_) => "PhysicalStorage",
+            Self::SubDirectory(_) => "SubDirectory",
+            Self::Online(_) => "OnlineStorage",
+        }
+    }
+
+    /// Short type name with one letter like "P".
+    pub fn shorttypename(&self) -> &str {
+        match self {
+            Self::PhysicalStorage(_) => "P",
+            Self::SubDirectory(_) => "S",
+            Self::Online(_) => "O",
+        }
+    }
+}
 
 impl StorageExt for Storage {
     fn name(&self) -> &String {