How to create a hidden file in Windows/Mac/Linux?

Windows:

SetFileAttributesW function

Sets the attributes for a file or directory.

FILE_ATTRIBUTE_HIDDEN 2 (0x2)

The file or directory is hidden. It is not included in an ordinary directory listing.

---

Go:

Package syscall

func SetFileAttributes

func SetFileAttributes(name *uint16, attrs uint32) (err error)

---

Convert from a Go UTF-8 encoded string (string) to a Windows UTF-16 encoded string pointer (*uint16).

Package syscall

func UTF16PtrFromString

func UTF16PtrFromString(s string) (*uint16, error)

UTF16PtrFromString returns pointer to the UTF-16 encoding of the UTF-8 string s, with a terminating NUL added. If s contains a NUL byte at any location, it returns (nil, EINVAL).

---

Use OS Build Contraints.

---

For example,

hide/attrib.go:

package main

import (
    "fmt"
    "io/ioutil"
    "os"
)

func main() {
    filename := `test.hidden.file`
    os.Remove(filename)
    os.Remove("." + filename)
    err := ioutil.WriteFile(filename, []byte(filename), 0666)
    if err != nil {
        fmt.Fprintln(os.Stderr, err)
        return
    }
    err = HideFile(filename)
    if err != nil {
        fmt.Fprintln(os.Stderr, err)
        return
    }
    fmt.Println("hidden:", filename)
}

hide/hide.go:

// +build !windows

package main

import (
    "os"
    "path/filepath"
    "strings"
)

func HideFile(filename string) error {
    if !strings.HasPrefix(filepath.Base(filename), ".") {
        err := os.Rename(filename, "."+filename)
        if err != nil {
            return err
        }
    }
    return nil
}

hide/hide_windows.go:

// +build windows

package main

import (
    "syscall"
)

func HideFile(filename string) error {
    filenameW, err := syscall.UTF16PtrFromString(filename)
    if err != nil {
        return err
    }
    err = syscall.SetFileAttributes(filenameW, syscall.FILE_ATTRIBUTE_HIDDEN)
    if err != nil {
        return err
    }
    return nil
}

Output (Linux):

$ tree hide
hide
├── attrib.go
├── hide.go
└── hide_windows.go
$

$ go build && ./hide
hidden: test.hidden.file
$ ls -a .test.hidden.file
.test.hidden.file
$ 

Output (Windows):

>go build && hide
hidden: test.hidden.file
>attrib test.hidden.file
A   H        \test.hidden.file
>