diff --git a/pttodoer/src/main.rs b/pttodoer/src/main.rs
index 3d599c0..5fa68d2 100644
--- a/pttodoer/src/main.rs
+++ b/pttodoer/src/main.rs
@@ -1,4 +1,5 @@
 use serde_yaml;
+use serde::ser::{Serialize};
 use serde;
 use chrono::{DateTime, Local};
 use chrono::naive::NaiveDateTime;
@@ -8,13 +9,14 @@ use clap::Parser;
 
 fn main() {
    let flags = Flags::new();
-   println!("{:?}", flags);
+   let db = DB::new(flags.path).unwrap();
+   println!("{}", db.due().to_string());
 }
 
 #[derive(Debug, Parser)]
 struct Flags {
-   #[arg(short = 'f', long = "file", default_value="$PTTODO_FILE")]
-   file: String,
+   #[arg(short = 'f', long = "path", default_value="$PTTODO_FILE")]
+   path: String,
 
    #[arg(short = 'a', long = "add")]
    add: Option<String>,
@@ -30,10 +32,10 @@ impl Flags {
    fn new() -> Flags {
       let mut result = Flags::parse();
 
-      if result.file.get(..1) == Some("$") {
-         result.file = std::env::var(
-            result.file.get(1..).unwrap()
-         ).expect(format!("'{}' unset", result.file).as_str());
+      if result.path.get(..1) == Some("$") {
+         result.path = std::env::var(
+            result.path.get(1..).unwrap()
+         ).expect(format!("'{}' unset", result.path).as_str());
       }
 
       result
@@ -222,6 +224,32 @@ impl Tasks {
       }
    }
 
+   pub fn to_string(&self) -> String {
+      let mut buffer = Vec::new();
+      let mut serializer = serde_yaml::Serializer::new(&mut buffer);
+      _ = serde_yaml::Value::Sequence(
+            self.0.iter()
+            .map(|x| {
+               let mut x = x.clone();
+               if x.is_due() {
+                  x.unset("ts".to_string());
+               }
+               x
+            })
+            .map(|x| {
+               let is = x.get_value("is".to_string());
+               if x.0.len() == 1 && is.is_some() {
+                  return is.unwrap();
+               }
+               serde_yaml::Value::from(x.0.clone())
+            })
+            .map(|x| serde_yaml::Value::from(x.clone()))
+            .collect()
+         ).serialize(&mut serializer)
+         .expect("failed to serialize");
+      String::from_utf8(buffer).expect("illegal utf8 characters found")
+   }
+
    pub fn len(&self) -> usize {
       self.0.len()
    }
@@ -379,6 +407,10 @@ impl Task {
       }
    }
 
+   fn unset(&mut self, k: String) {
+      self.0.remove(serde_yaml::Value::String(k));
+   }
+
    #[allow(dead_code)] // used in test
    fn set(&mut self, k: String, v: String) {
       self.0.insert(