Just another update

Task/Take-notes-on-the-command-line/Go/take-notes-on-the-command-line.go

@@ -1,46 +1,49 @@
 package main
 
 import (
-    "fmt"
-    "io"
-    "os"
-    "strings"
-    "time"
+	"fmt"
+	"io"
+	"os"
+	"strings"
+	"time"
 )
 
-const fn = "NOTES.TXT"
+func addNote(fn string, note string) error {
+	f, err := os.OpenFile(fn, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0666)
+	if err != nil {
+		return err
+	}
+	_, err = fmt.Fprint(f, time.Now().Format(time.RFC1123), "\n\t", note, "\n")
+	// To be extra careful with errors from Close():
+	if cErr := f.Close(); err == nil {
+		err = cErr
+	}
+	return err
+}
+
+func showNotes(w io.Writer, fn string) error {
+	f, err := os.Open(fn)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return nil // don't report "no such file"
+		}
+		return err
+	}
+	_, err = io.Copy(w, f)
+	f.Close()
+	return err
+}
 
 func main() {
-    if len(os.Args) == 1 {
-        f, err := os.Open(fn)
-        if err != nil {
-            // don't report "file does not exist" as an error, but
-            // if it seems to be there but just can't be opened for
-            // some reason, print original error from open attempt.
-            if _, statErr := os.Stat(fn); statErr == nil {
-                fmt.Println(err)
-            }
-            return
-        }
-        if _, err = io.Copy(os.Stdout, f); err != nil {
-            fmt.Println(err)
-        }
-        if cErr := f.Close(); err == nil && cErr != nil {
-            fmt.Println(err)
-        }
-        return
-    }
-    f, err := os.OpenFile(fn, os.O_RDWR|os.O_APPEND|os.O_CREATE, 0666)
-    if err != nil {
-        fmt.Println(err)
-        return
-    }
-    _, err = fmt.Fprint(f, time.Now().Format(time.RFC1123),
-        "\n\t", strings.Join(os.Args[1:], " "), "\n")
-    if err != nil {
-        fmt.Println(err)
-    }
-    if cErr := f.Close(); err == nil && cErr != nil {
-        fmt.Println(cErr)
-    }
+	const fn = "NOTES.TXT"
+	var err error
+	if len(os.Args) > 1 {
+		err = addNote(fn, strings.Join(os.Args[1:], " "))
+	} else {
+		err = showNotes(os.Stdout, fn)
+	}
+	if err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
 }