# 1. 获取用户要复制的文件名
old_file_name = input("请输入要复制的文件名:")

# 2. 打开要复制的文件
old_file = open(old_file_name, "r")

# test.py  -----> test[复件].py
# new_file_name = "[复件]"+old_file_name
position = old_file_name.rfind(".")
new_file_name = old_file_name[:position] + "[复件]" + old_file_name[position:]

# 3. 新建一个文件
# new_file = open("laowang.txt", "w")
new_file = open(new_file_name, "w")

# 4. 从旧文件中读取数据,并且写入到新文件中
while True:
    content = old_file.read(1024)

    if len(content) == 0:
        break

    new_file.write(content)

# 5. 关闭2个文件
old_file.close()
new_file.close()

每次读取1024个字节
每次写入1024个字节