diff --git a/wfassoc-exec/src/old_main.rs b/wfassoc-exec/src/old_main.rs
deleted file mode 100644
index ca633ea..0000000
--- a/wfassoc-exec/src/old_main.rs
+++ /dev/null
@@ -1,162 +0,0 @@
-pub(crate) mod cli;
-pub(crate) mod manifest;
-
-use clap::Parser;
-use cli::{Cli, Commands, Target};
-use comfy_table::Table;
-use manifest::Manifest;
-use std::collections::HashMap;
-use std::process;
-use thiserror::Error as TeError;
-use wfassoc::{Program, Scope, Token, View};
-
-// region: Basic Types
-
-/// All errors occurs in this executable.
-#[derive(TeError, Debug)]
-enum Error {
-    /// Error from wfassoc core.
-    #[error("{0}")]
-    Core(#[from] wfassoc::Error),
-    /// Error when parsing manifest TOML file.
-    #[error("invalid manifest file: {0}")]
-    Manifest(#[from] manifest::Error),
-
-    /// Error when specifying invalid manner name for extension.
-    #[error("extension {ext} associated manner {manner} is invalid in manifest file")]
-    InvalidMannerName { manner: String, ext: String },
-}
-
-/// Result type used in this executable.
-type Result<T> = std::result::Result<T, Error>;
-
-// endregion
-
-// region: Correponding Runner
-
-struct Composition {
-    program: Program,
-    ext_tokens: Vec<Token>,
-}
-
-impl Composition {
-    pub fn new(cli: &Cli) -> Result<Composition> {
-        // Open file and read manifest TOML file
-        let mf = Manifest::from_file(&cli.config_file)?;
-        // Create instance
-        let mut program = Program::new(&mf.identifier, &cli.config_file)?;
-        // Setup manner
-        let mut manner_token_map: HashMap<&str, Token> = HashMap::new();
-        for (k, v) in mf.manners.iter() {
-            let token = program.add_manner(v.as_str())?;
-            manner_token_map.insert(k.as_str(), token);
-        }
-        // Setup extension
-        let mut ext_tokens = Vec::new();
-        for (k, v) in mf.exts.iter() {
-            let token = match manner_token_map.get(v.as_str()) {
-                Some(v) => v,
-                None => {
-                    return Err(Error::InvalidMannerName {
-                        manner: v.to_string(),
-                        ext: k.clone(),
-                    });
-                }
-            };
-            let token = program.add_ext(k.as_str(), *token)?;
-            ext_tokens.push(token);
-        }
-        // Okey
-        Ok(Self {
-            program,
-            ext_tokens,
-        })
-    }
-
-    pub fn get_program(&self) -> &Program {
-        &self.program
-    }
-
-    pub fn iter_ext_tokens(&self) -> impl Iterator<Item = Token> {
-        self.ext_tokens.iter().copied()
-    }
-}
-
-fn run_register(cli: &Cli, target: &Target) -> Result<()> {
-    let composition = Composition::new(cli)?;
-    let scope = target.clone().into();
-
-    // Register program
-    let program = composition.get_program();
-    program.register(scope)?;
-    // Link all file extensions
-    for token in composition.iter_ext_tokens() {
-        program.link_ext(token, scope)?;
-    }
-    
-    println!("Register OK.");
-    Ok(())
-}
-
-fn run_unregister(cli: &Cli, target: &Target) -> Result<()> {
-    let composition = Composition::new(cli)?;
-    let scope = target.clone().into();
-
-    // Unlink all file extensions
-    let program = composition.get_program();
-    for token in composition.iter_ext_tokens() {
-        program.unlink_ext(token, scope)?;
-    }
-    // Unregister prorgam
-    program.unregister(scope)?;
-
-    println!("Unregister OK.");
-    Ok(())
-}
-
-fn run_query(cli: &Cli) -> Result<()> {
-    let composition = Composition::new(cli)?;
-
-    // Show file association
-    let mut table = Table::new();
-    table.set_header(["Extension", "Hybrid", "User", "System"]);
-
-    let program = composition.get_program();
-    for token in composition.iter_ext_tokens() {
-        let cell_ext = program.get_ext_str(token).unwrap();
-        let cell_hybrid = program
-            .query_ext(token, View::Hybrid)?
-            .map(|pi| pi.to_string())
-            .unwrap_or_default();
-        let cell_user = program
-            .query_ext(token, View::User)?
-            .map(|pi| pi.to_string())
-            .unwrap_or_default();
-        let cell_system = program
-            .query_ext(token, View::System)?
-            .map(|pi| pi.to_string())
-            .unwrap_or_default();
-
-        table.add_row([cell_ext, cell_hybrid, cell_user, cell_system]);
-    }
-
-    println!("{table}");
-
-    Ok(())
-}
-
-// endregion
-
-fn main() {
-    let cli = Cli::parse();
-
-    let rv = match &cli.command {
-        Commands::Register { target } => run_register(&cli, target),
-        Commands::Unregister { target } => run_unregister(&cli, target),
-        Commands::Query => run_query(&cli),
-    };
-    rv.unwrap_or_else(|e| {
-        eprintln!("Runtime error: {}.", e);
-        process::exit(1)
-    });
-}
diff --git a/wfassoc-exec/src/runner.rs b/wfassoc-exec/src/runner.rs
index fc3f896..18a5058 100644
--- a/wfassoc-exec/src/runner.rs
+++ b/wfassoc-exec/src/runner.rs
@@ -82,11 +82,15 @@ fn stringified_exts_to_indices(
 // region: Respective Runners
 
 fn run_register(mut program: wfassoc::Program, scope: wfassoc::Scope) -> Result<()> {
-    Ok(program.register(scope)?)
+    program.register(scope)?;
+    println!("Application now is installed.");
+    Ok(())
 }
 
 fn run_unregister(mut program: wfassoc::Program, scope: wfassoc::Scope) -> Result<()> {
-    Ok(program.unregister(scope)?)
+    program.unregister(scope)?;
+    println!("Application now is uninstalled.");
+    Ok(())
 }
 
 fn run_status(program: wfassoc::Program, scope: wfassoc::Scope) -> Result<()> {
@@ -108,6 +112,8 @@ fn run_ext_link(
     for index in exts {
         program.link_ext(scope, index)?;
     }
+
+    println!("File extension now is linked.");
     Ok(())
 }
 
@@ -120,6 +126,8 @@ fn run_ext_unlink(
     for index in exts {
         program.link_ext(scope, index)?;
     }
+    
+    println!("File extension now is unlinked.");
     Ok(())
 }