参考:
https://www.tecmint.com/clear-ram-memory-cache-buffer-and-swap-space-on-linux/
https://linux.cn/article-5627-1.html
sync && sudo sh -c 'echo 3 > /proc/sys/vm/drop_caches' && sudo swapoff -a && sudo swapon -a && printf ' %s ' 'Ram-cache and Swap Cleared'