tool function:
Binwalk is a fast, easy to use tool for analyzing, reverse engineering, and extracting firmware images.
how to install:
apt-get install binwalk.
how to use it:
example: binwalk -E rootfs.img
File storage location distribution in firmware using binwalk
原文：https://www.cnblogs.com/lianghong881018/p/10156599.html