diff --git a/src/bin/dmc/cst.rs b/src/bin/dmc/cst.rs
new file mode 100644
index 0000000..231fe2a
--- /dev/null
+++ b/src/bin/dmc/cst.rs
@@ -0,0 +1,30 @@
+use deimos::parser::{DeimosParser, Rule};
+use std::path::PathBuf;
+use pest::iterators::{Pair, Pairs};
+use pest::Parser;
+
+fn print_pair(pair: Pair<Rule>) {
+    println!("{:?}", pair.as_rule());
+    println!("{:?}", pair.as_span());
+    println!("----");
+    print_pairs(pair.into_inner());
+}
+
+fn print_pairs(pairs: Pairs<Rule>) {
+    for pair in pairs {
+        print_pair(pair);
+    }
+}
+
+pub fn show_cst(path: &PathBuf) {
+    let src = std::fs::read_to_string(path).unwrap();
+    let parse_result = DeimosParser::parse(Rule::CompilationUnit, &src);
+    match parse_result {
+        Ok(pairs) => {
+            print_pairs(pairs);
+        }
+        Err(error) => {
+            eprintln!("{:?}", error);
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/bin/dmc/main.rs b/src/bin/dmc/main.rs
index 535c491..d09feb3 100644
--- a/src/bin/dmc/main.rs
+++ b/src/bin/dmc/main.rs
@@ -1,3 +1,4 @@
+mod cst;
 mod ir;
 mod name_analysis;
 mod p3;
@@ -5,11 +6,12 @@ mod p3;
 
 use std::path::PathBuf;
 
+// use crate::unparse::unparse;
+use crate::cst::show_cst;
+use crate::ir::compile_to_ir;
 use crate::name_analysis::name_analysis;
 use crate::p3::pretty_print_parse;
-// use crate::unparse::unparse;
 use clap::{Parser, Subcommand};
-use crate::ir::compile_to_ir;
 
 #[derive(Debug, Parser)]
 #[command(name = "dmc")]
@@ -21,46 +23,36 @@ struct Cli {
 
 #[derive(Debug, Subcommand)]
 enum Commands {
-    #[command(arg_required_else_help = true)]
-    Unparse {
-        paths: Vec<PathBuf>,
-    },
-    P3 {
-        paths: Vec<PathBuf>,
-    },
-    NameAnalysis {
-        paths: Vec<PathBuf>,
-    },
-    Ir {
-        paths: Vec<PathBuf>,
-    }
+    Cst { paths: Vec<PathBuf> },
+    P3 { paths: Vec<PathBuf> },
+    NameAnalysis { paths: Vec<PathBuf> },
+    Ir { paths: Vec<PathBuf> },
 }
 
 fn main() {
     let args = Cli::parse();
     match args.command {
-        // Commands::Unparse { paths } => {
-        //     for path in paths {
-        //         unparse(&path);
-        //     }
-        // }
+        Commands::Cst { paths } => {
+            for path in &paths {
+                show_cst(path);
+            }
+        }
         Commands::P3 { paths } => {
             for path in paths {
-                pretty_print_parse(&path)
+                pretty_print_parse(&path);
             }
         }
         Commands::NameAnalysis { paths } => {
             let result = name_analysis(&paths);
             if let Err(e) = result {
-                eprintln!("{}", e)
+                eprintln!("{}", e);
             }
         }
         Commands::Ir { paths } => {
             let result = compile_to_ir(&paths);
             if let Err(e) = result {
-                eprintln!("{}", e)
+                eprintln!("{}", e);
             }
         }
-        _ => todo!(),
     }
 }