#MySQL Safe Update ("Dummy") Mode
mysql --safe-updates
or mysql --i-am-a-dummy
Requires you to use unique identifiers when deleting rows, thus helping to prevent you from inadvertently emptying the table. For example, delete from users where 1=1 will fail since an identifying column isn't used.
Hat Tip: This HN thread: https://news.ycombinator.com/item?id=11342968