func PathExists(path string) (bool, error) {
	var err error
	if _, err = os.Stat(path); err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return true, err
}
PathExists check up file or directory existence.
package wpk
import (
	"bytes"
	"io"
	"io/fs"
	"os"
	"path"
	"path/filepath"
	"regexp"
	"strings"
)
var efre = regexp.MustCompile(`\$\{\w+\}`)
func Envfmt(p string) string {
	return filepath.ToSlash(efre.ReplaceAllStringFunc(p, func(name string) string {
		return os.Getenv(name[2 : len(name)-1])  
	}))
}