filename = "*****.***"
BUFF_LEN = 1000

def ReadGen(genFile):
    while(True):
        buff = genFile.read(BUFF_LEN)
        if not buff: return
        yield buff

for i, buff in enumerate(ReadGen(open(filename, "rb"))):
    open(str(i) + '_' + filename, "wb").write(buff)

f = open("test.txt", "w")
for i in range(10000):
    f.write("Fish\n")
f.close()

f = open("test.txt", "r")
f_ = open("test_.txt", "w")
data = f.read(1000)
f_.write(data)
f_.close()
f.close()