find ../ImageAll_V1_part1/mask/ -maxdepth 1 -type f | sort | head -n 40 | xargs cp -t ./
https://askubuntu.com/questions/662339/sort-files-alphabetically-before-processing
https://unix.stackexchange.com/questions/29214/copy-first-n-files-in-a-different-directory
using find with xargs: