file/edit.go
func Replace(filename string, r []Replacer) error {
	e, err := NewEdit(filename)
	if err != nil {
		return err
	}

	err = e.genReplace(r, -1)
	err2 := e.Close()
	if err != nil {
		return err
	}
	return err2
}
func Replace(filename string, r []Replacer) error {
	e, err := NewEdit(filename)
	if err != nil {
		return err
	}

	err = e.genReplace(r, -1)
	err2 := e.Close()
	if err != nil {
		return err
	}
	return err2
}
/*// Insert writes len(b) bytes at the start of the named file. It returns an
// error, if any. The file is backed up.
func Insert(filename string, b []byte) error {
	e, err := NewEdit(filename)
	if err != nil {
		return err
	}

	err = e.Insert(b)
	err2 := e.Close()
	if err != nil {
		return err
	}
	return err2
}

// InsertString is like Insert, but writes the contents of string s rather than
// an array of bytes.
func InsertString(filename, s string) error {
	return Insert(filename, []byte(s))
}*/
// Replace replaces all regular expressions mathed in r for the named file.