Move a file to a different drive with Go - go

Question

I'm trying to move a file from my C-drive to my H-drive using os.Replace().
The code looks as follows:
func MoveFile(source string, destination string) {
err := os.Rename(source, destination)
if err != nil {
fmt.Println(err)
}
}
However, when I run the code I get the following error:
rename C:\old\path\to\file.txt H:\new\path\to\file.txt: The system cannot move the file to a different disk drive.
I found this issue on GitHub that specifies the problem but it appears that they will not change this function to allow it to move file on different disk drives.
I already searched for other possibilities to move files, but found nothing in the standard documentation or the internet.
So, what should I do now to be able to move files on different disk drives?

Answer 1

As the comment said, you'll need to create a new file on the other disk, copy the contents, and then remove the original. It's straightforward using os.Create, io.Copy, and os.Remove:
import (
"fmt"
"io"
"os"
)
func MoveFile(sourcePath, destPath string) error {
inputFile, err := os.Open(sourcePath)
if err != nil {
return fmt.Errorf("Couldn't open source file: %s", err)
}
outputFile, err := os.Create(destPath)
if err != nil {
inputFile.Close()
return fmt.Errorf("Couldn't open dest file: %s", err)
}
defer outputFile.Close()
_, err = io.Copy(outputFile, inputFile)
inputFile.Close()
if err != nil {
return fmt.Errorf("Writing to output file failed: %s", err)
}
// The copy was successful, so now delete the original file
err = os.Remove(sourcePath)
if err != nil {
return fmt.Errorf("Failed removing original file: %s", err)
}
return nil
}

Answer 2

You need to make sure that you handle all cases on both Linux and Windows. For example, for any size file,
package main
import (
"flag"
"fmt"
"io"
"os"
)
func MoveFile(source, destination string) (err error) {
src, err := os.Open(source)
if err != nil {
return err
}
defer src.Close()
fi, err := src.Stat()
if err != nil {
return err
}
flag := os.O_WRONLY | os.O_CREATE | os.O_TRUNC
perm := fi.Mode() & os.ModePerm
dst, err := os.OpenFile(destination, flag, perm)
if err != nil {
return err
}
defer dst.Close()
_, err = io.Copy(dst, src)
if err != nil {
dst.Close()
os.Remove(destination)
return err
}
err = dst.Close()
if err != nil {
return err
}
err = src.Close()
if err != nil {
return err
}
err = os.Remove(source)
if err != nil {
return err
}
return nil
}
func main() {
var src, dst string
flag.StringVar(&src, "src", "", "source file")
flag.StringVar(&dst, "dst", "", "destination file")
flag.Parse()
if src == "" || dst == "" {
flag.Usage()
os.Exit(1)
}
err := MoveFile(src, dst)
if err != nil {
fmt.Fprintln(os.Stderr, err)
os.Exit(1)
}
fmt.Printf("moved %q to %q\n", src, dst)
}
Output (Linux):
$ cp move.file src.file && go build movefile.go && ./movefile -src=src.file -dst=dst.file
moved "src.file" to "dst.file"
$
Output (Windows):
>copy /Y move.file src.file && go build movefile.go && movefile -src=src.file -dst=dst.file
moved "src.file" to "dst.file"
>

Answer 3

This solution Moves the file and preserves permissions:
func MoveFile(src, dst string) error {
in, err := os.Open(src)
if err != nil {
return fmt.Errorf("Couldn't open source file: %s", err)
}
out, err := os.Create(dst)
if err != nil {
in.Close()
return fmt.Errorf("Couldn't open dest file: %s", err)
}
defer out.Close()
_, err = io.Copy(out, in)
in.Close()
if err != nil {
return fmt.Errorf("Writing to output file failed: %s", err)
}
err = out.Sync()
if err != nil {
return fmt.Errorf("Sync error: %s", err)
}
si, err := os.Stat(src)
if err != nil {
return fmt.Errorf("Stat error: %s", err)
}
err = os.Chmod(dst, si.Mode())
if err != nil {
return fmt.Errorf("Chmod error: %s", err)
}
err = os.Remove(src)
if err != nil {
return fmt.Errorf("Failed removing original file: %s", err)
}
return nil
}
If only want to Copy the file without remove the original:
func CopyFile(src, dst string) error {
in, err := os.Open(src)
if err != nil {
return fmt.Errorf("Couldn't open source file: %s", err)
}
out, err := os.Create(dst)
if err != nil {
in.Close()
return fmt.Errorf("Couldn't open dest file: %s", err)
}
defer out.Close()
_, err = io.Copy(out, in)
in.Close()
if err != nil {
return fmt.Errorf("Writing to output file failed: %s", err)
}
err = out.Sync()
if err != nil {
return fmt.Errorf("Sync error: %s", err)
}
si, err := os.Stat(src)
if err != nil {
return fmt.Errorf("Stat error: %s", err)
}
err = os.Chmod(dst, si.Mode())
if err != nil {
return fmt.Errorf("Chmod error: %s", err)
}
return nil
}

Answer 4

Maybe you can use a magic approach, just using the syscall.MoveFile as follows.
func main() {
oldpath := "D:\\black.txt"
newpath := "E:\\black-new.txt"
from, _ := syscall.UTF16PtrFromString(oldpath)
to, _ := syscall.UTF16PtrFromString(newpath)
fmt.Println(*from, *to)
err := syscall.MoveFile(from, to)
if err != nil {
panic(err)
}
}
the program works.
if you want a cross-platform compatibility program, you can implement your own MoveFile.
func MoveFile(src string, dst string) error {
if runtime.GOOS == "windows" {
from, _ := syscall.UTF16PtrFromString(src)
to, _ := syscall.UTF16PtrFromString(dst)
return syscall.MoveFile(from, to)
} else {
return os.Rename(src, dst)
}
}