As indicated in comments, the way to get the last file can be:
ls -Art | tail -n 1
If you wrap it within $()
, it will be evaluated whenever you place it. Hence, you can do:
/usr/bin/mysql -u root -pexpress azuzDB < /home/admin/Desktop/backups/$(ls -Art /home/admin/Desktop/backups -Art | tail -n 1)