use robocopy for copying and moving on windows

Mentioned in #12.

nav.go

@@ -7,6 +7,7 @@ import (
 	"os"
 	"os/exec"
 	"path/filepath"
+	"runtime"
 	"sort"
 	"strings"
 )
@@ -512,16 +513,35 @@ func (nav *nav) put() error {
 
 	dir := nav.currDir()
 
+	var sh string
 	var args []string
 
-	var sh string
+	if runtime.GOOS == "windows" {
+		sh = "robocopy"
+		if !copy {
+			args = []string{"/move"}
+		}
+		for _, f := range list {
+			stat, err := os.Stat(f)
+			if err != nil {
+				log.Printf("getting file information: %s", err)
+				continue
+			}
+			base := filepath.Base(f)
+			dest := filepath.Dir(f)
+			if stat.IsDir() {
+				exec.Command(sh, append(args, f, filepath.Join(dir.path, base))...).Run()
+			} else {
+				exec.Command(sh, append(args, dest, dir.path, base)...).Run()
+			}
+		}
+	} else {
 		if copy {
 			sh = "cp"
 			args = append(args, "-r")
 		} else {
 			sh = "mv"
 		}
-
 		args = append(args, "--backup=numbered")
 		args = append(args, list...)
 		args = append(args, dir.path)
@@ -531,6 +551,7 @@ func (nav *nav) put() error {
 		if err := cmd.Run(); err != nil {
 			return fmt.Errorf("%s: %s", sh, err)
 		}
+	}
 
 	// TODO: async?