linux bin & sbin different
flutter & $PATH
http://blog.taylormcgann.com/2014/04/11/difference-bin-sbin/
https://unix.stackexchange.com/questions/26047/how-to-correctly-add-a-path-to-path
https://stackoverflow.com/questions/26801895/the-different-between-android-foldersbin-xbin-sbin
difference between bin and sbin in linux
https://answers.yahoo.com/question/index?qid=20060708005540AA3qYc8
These are all conventions, and no a hard and fast rule, but in general, bin contains programs whereas sbin contains scripts.
这些都是约定，没有硬性规则，但一般来说，bin 包含程序，而 sbin 包含脚本。
https://www.linuxquestions.org/questions/linux-software-2/bin-vs-sbin-96063/