A bunch of changes

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

cmd/onerng/image.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"os"
+
+	"github.com/pkg/errors"
+
+	"github.com/hairyhenderson/go-onerng"
+	"github.com/spf13/cobra"
+)
+
+// imageCmd represents the image command
+func imageCmd(ctx context.Context) *cobra.Command {
+	var imgOut string
+	cmd := &cobra.Command{
+		Use:   "image",
+		Short: "Dump the OneRNG's firmware image",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			o := onerng.OneRNG{Path: opts.Device}
+			err := o.Init(ctx)
+			if err != nil {
+				return errors.Wrapf(err, "init failed before image extraction")
+			}
+			image, err := o.Image(ctx)
+			if err != nil {
+				return err
+			}
+			var out *os.File
+			if imgOut == "-" {
+				out = os.Stdout
+			} else {
+				out, err = os.OpenFile(imgOut, os.O_RDWR|os.O_CREATE, 0644)
+				if err != nil {
+					return err
+				}
+			}
+			n, err := out.Write(image)
+			fmt.Fprintf(os.Stderr, "Wrote %db to %s\n", n, imgOut)
+			return err
+		},
+	}
+	cmd.Flags().StringVarP(&imgOut, "out", "o", "onerng.img", "output file for image (use - for stdout)")
+	return cmd
+}