Adding upstream version 1.2.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>

cmd/selfupdate-example/main.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+	"github.com/blang/semver"
+	"github.com/rhysd/go-github-selfupdate/selfupdate"
+	"os"
+)
+
+const version = "1.2.3"
+
+func selfUpdate(slug string) error {
+	selfupdate.EnableLog()
+
+	previous := semver.MustParse(version)
+	latest, err := selfupdate.UpdateSelf(previous, slug)
+	if err != nil {
+		return err
+	}
+
+	if previous.Equals(latest.Version) {
+		fmt.Println("Current binary is the latest version", version)
+	} else {
+		fmt.Println("Update successfully done to version", latest.Version)
+		fmt.Println("Release note:\n", latest.ReleaseNotes)
+	}
+	return nil
+}
+
+func usage() {
+	fmt.Fprintln(os.Stderr, "Usage: selfupdate-example [flags]\n")
+	flag.PrintDefaults()
+}
+
+func main() {
+	help := flag.Bool("help", false, "Show this help")
+	ver := flag.Bool("version", false, "Show version")
+	update := flag.Bool("selfupdate", false, "Try go-github-selfupdate via GitHub")
+	slug := flag.String("slug", "rhysd/go-github-selfupdate", "Repository of this command")
+
+	flag.Usage = usage
+	flag.Parse()
+
+	if *help {
+		usage()
+		os.Exit(0)
+	}
+
+	if *ver {
+		fmt.Println(version)
+		os.Exit(0)
+	}
+
+	if *update {
+		if err := selfUpdate(*slug); err != nil {
+			fmt.Fprintln(os.Stderr, err)
+			os.Exit(1)
+		}
+		os.Exit(0)
+	}
+
+	usage()
+}