From 10150a5d98c553366117f4e170cbf0dc2859d5ce Mon Sep 17 00:00:00 2001
From: high-moctane <high.moctane@gmail.com>
Date: Tue, 1 Oct 2019 18:21:29 +0900
Subject: [PATCH] wrote a simple usage.

---
 main.go | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/main.go b/main.go
index 3b3cdb9..e9905da 100644
--- a/main.go
+++ b/main.go
@@ -22,7 +22,19 @@ func main() {
 
 func run() int {
 	if !parseArgs() {
+		help := `The nextword prints the most likely English words that follow the stdin sentence.
+
+The space character at the end of line plays an important role. If the line ends
+with a space, the command show the next suggested words. However, if the line
+ends with an alphabetic character, the suggested words start with the last word
+of the line.
+
+This command needs an external dataset. The dataset path should be set in an
+environment value "$NEXTWORD_DATA_PATH". `
+
 		flag.Usage()
+		fmt.Fprintln(os.Stderr, "")
+		fmt.Fprintln(os.Stderr, help)
 		return 1
 	}