MLog

$mysqldump -u ID -p PASSWORD -A > All.sql -A, --all-databases Dump all the databases. This will be same as --databases

$ls -l | grep "^d" ^는 이 문자로 시작한다는 뜻

$ rm -rf -f, --force ignore nonexistent files, never prompt -r, -R, --recursive remove directories and their contents recursively