Golang : How to check if a file is hidden?

So, how to check if a file is hidden? The solutions below are OS dependent. One for Unix/Linux and another for Windows. It is pretty straightforward to check if a file is hidden under Linux/Unix, but more complicated under Windows.

For Linux/Unix:

 package main

 import (

  "fmt"
  "log"
  "os"
  "runtime"
 )

 func IsHidden(filename string) (bool, error) {

  if runtime.GOOS != "windows" {

 // unix/linux file or directory that starts with . is hidden
 if filename[0:1] == "." {
 return true, nil

 } else {
 return false, nil
 }

  } else {
 log.Fatal("Unable to check if file is hidden under this OS")
  }
 return false, nil
 }

 func main() {
  if len(os.Args) != 2 {
 fmt.Printf("Usage : %s <filename>\n", os.Args[0])
 os.Exit(0)
  }

  filename := os.Args[1]

  result, err := IsHidden(filename)
  if err != nil {
 log.Println(err)
  }
  log.Println("["+filename+"]", "is hidden? ", result)

 }

Sample output:

$ ./fileishidden .vscode

2017/04/26 10:35:10 .vscode is hidden? true

$ ./fileishidden work

2017/04/26 10:35:58 [work] is hidden? false

$ ./fileishidden .themes

2017/04/26 10:36:03 [.themes] is hidden? true

NOTE: I'd tried to build a cross-platform solution, but compiling the code below under Linux will generate these errors:

# command-line-arguments

./fileishiddenwindows.go:18: undefined: syscall.UTF16PtrFromString

./fileishiddenwindows.go:22: undefined: syscall.GetFileAttributes

./fileishiddenwindows.go:26: undefined: syscall.FILE_ATTRIBUTE_HIDDEN

However, everything is fine when compiling under Windows. Somehow, the Windows related functions are not available under Linux. Maybe changing the target platform will be helpful.

For Windows:

 package main

 import (
  // use golang.org/x/sys/windows package in case syscall package has missing
  // GetFileAttributes
  //"golang.org/x/sys/windows"
  "fmt"
  "log"
  "os"
  "runtime"
  "syscall"
 )

 func IsHidden(filename string) (bool, error) {

  if runtime.GOOS == "windows" {

 pointer, err := syscall.UTF16PtrFromString(filename)
 if err != nil {
 return false, err
 }
 attributes, err := syscall.GetFileAttributes(pointer)
 if err != nil {
 return false, err
 }
 return attributes&syscall.FILE_ATTRIBUTE_HIDDEN != 0, nil
  } else {
 log.Fatal("Unable to invoke GetFileAttributes() function or FILE_ATTRIBUTE_HIDDEN property")
  }
 return false, nil
 }

 func main() {
  if len(os.Args) != 2 {
 fmt.Printf("Usage : %s <filename>\n", os.Args[0])
 os.Exit(0)
  }

  filename := os.Args[1]

  result, err := IsHidden(filename)
  if err != nil {
 log.Println(err)
  }
  log.Println(filename, "is hidden? ", result)

 }

Sample output:

References:

http://grokbase.com/t/gg/golang-nuts/144va1n8w5/go-nuts-how-do-check-if-file-or-directory-is-hidden-under-windows

https://msdn.microsoft.com/en-us/library/windows/desktop/aa364944(v=vs.85).aspx