Golang bad file descriptor (how to append to a file)

Golang bad file descriptor

Golang updating a file #

When you use Golang, Its really a good idea, playing with files is actually fun, however this popular error, occurs when you want to update or append to a file, without deleteing the text written already.

Golang creating a file #

This is only possible if you want to write to the file for the first time.

f, err := os.Create(fileName)
if err != nil {
    return err
}
_, err = f.WriteString("text")
if err != nil {
    return err
}

Golang updating a file #

This is how you open a file, and append to it.

f, err := os.OpenFile(fileName, os.O_CREATE|os.O_WRONLY|os.O_APPEND, os.ModePerm)
// the args: os.O_CREATE|os.O_WRONLY|os.O_APPEND, os.ModePerm
//f, err := os.Create(fileName)
if err != nil {
    return err
}
_, err = f.WriteString("text")
if err != nil {
    return err
}

for more inforamtions please referr to this stackoverflow link.