June 2018 Update

Task/Take-notes-on-the-command-line/Rust/take-notes-on-the-command-line.rust

@@ -0,0 +1,44 @@
+extern crate chrono;
+
+use std::fs::OpenOptions;
+use std::io::{self, BufReader, BufWriter};
+use std::io::prelude::*;
+use std::env;
+
+const FILENAME: &str = "NOTES.TXT";
+
+fn show_notes() -> Result<(), io::Error> {
+    let file = OpenOptions::new()
+        .read(true)
+        .create(true) // create the file if not found
+        .write(true) // necessary to create the file
+        .open(FILENAME)?;
+    let mut buf_reader = BufReader::new(file);
+    let mut contents = String::new();
+    buf_reader.read_to_string(&mut contents)?;
+    println!("{}", contents);
+    Ok(())
+}
+
+fn add_to_notes(note: &str) -> Result<(), io::Error> {
+    let file = OpenOptions::new()
+        .append(true) // disables overwriting, writes to the end of the file
+        .create(true)
+        .open(FILENAME)?;
+    let mut buf_writer = BufWriter::new(file);
+
+    let date_and_time = chrono::Local::now();
+    writeln!(buf_writer, "{}", date_and_time)?;
+
+    writeln!(buf_writer, "\t{}", note)
+}
+
+fn main() {
+    let note = env::args().skip(1).collect::<Vec<_>>();
+
+    if note.is_empty() {
+        show_notes().expect("failed to print NOTES.TXT");
+    } else {
+        add_to_notes(&note.join(" ")).expect("failed to write to NOTES.TXT");
+    }
+}