start undocker

main.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"errors"
+
+	goflags "github.com/jessevdk/go-flags"
+)
+
+type opts struct {
+	PositionalArgs struct {
+		Infile     goflags.Filename `long:"infile" description:"Docker container tarball"`
+		Outfile string           `long:"outfile" description:"Output tarball"`
+	} `positional-args:"yes" required:"yes"`
+}
+
+func main() {
+	if err := run(os.Args); err != nil {
+		os.Exit(1)
+	}
+	os.Exit(0)
+}
+
+func run(args []string) error {
+	var flags opts
+	args1, err := goflags.ParseArgs(&flags, args)
+	if err != nil {
+		return err
+	}
+	if len(args1) != 0 {
+		return errors.New("too many args")
+	}
+
+	fmt.Printf("infile: %s\n", flags.PositionalArgs.Infile)
+	fmt.Printf("outfile: %s\n", flags.PositionalArgs.Outfile)
+
+	return nil
+}