python大文件读取
https://stackoverflow.com/questions/8009882/how-to-read-a-large-file-line-by-line-in-python
https://blog.csdn.net/lanchunhui/article/details/51581540
https://blog.csdn.net/qq_17550379/article/details/80212131
https://blog.csdn.net/u012762054/article/details/78384294
https://blog.csdn.net/qq_38461388/article/details/82144548
cmd:wc -l