main-appenParts.go

func addParts(filename string, files []string) {
	// filename : filename of full file.
	// files : array of filenames of parts.
	
	// Create if not found and open mode as append..
	// So writing means adding.
	out, err := os.OpenFile(filename, os.O_CREATE|os.O_APPEND|os.O_WRONLY, 0600)
	// usual.
	check err

	// loop through `files` and write (add) it to the resulting file.
	for _, val := range files {
		f, err := os.Open(val)
		check err
		_, err = io.Copy(out, f)
		check err
		f.Close()
		// Remove the temp file too...
		os.Remove(val)
	}
	
	// Close the output file.
	out.Close()
}