How to make sql-mode=”NO_ENGINE_SUBSTITUTION” permanent in MySQL my.cnf

Question

Just to add my configuration to the mix, I’m using MySQL 5.7.8 which has the same strict sql_mode rules by default.

I finally figured the following working in my /etc/mysql/my.conf:
```
[mysqld]
sql-mode="STRICT_TRANS_TABLES,NO_ENGINE_SUBSTITUTION"
```

i.e. dash, not underscore and quotes around the value.

I have NO other my.conf files other than /etc/mysql/my.conf
There are some extra config includes being loaded from /etc/mysql/conf.d/ but they are blank.

And that seems to work for me.