sys 會比較像是透過 python 取得 "系統" 相關的參數,例如:作業系統種類、python 版本... 等等
os 則比較偏向於實際對作業系統下命令,像常見的 os.lsitdir() 取得該目錄下所有的檔案,基本上就等價於 windows 的 dir、linux 的 ls
The summary is that the OS module is responsible for interacting with the operating system, providing access to the underlying interface of the operating system, and the SYS module is responsible for the interaction between the program and the Python interpreter, providing a series of functions and variables for manipulating the Python runtime environment.