creates the required hash

def get_hash(fName, readSize, dire=pDir()):
    """
    creates the required hash
    """
    if not fileExists(fName, dire):
        return -1
    readSize = readSize * 1024 # bytes to be read
    fName = os.path.join(dire, fName) # name coupled with path
    with open(fName, 'rb') as f:
        size = os.path.getsize(fName)
        if size < readSize * 2:
            return -1
        data = f.read(readSize)
        f.seek(-readSize, os.SEEK_END)
        data += f.read(readSize)
    return md5(data).hexdigest()