sudo mysql_secure_installation : command not found

This answer help me and I've installed mysql-server-core-5.7 but I got an error :

sudo mysql_secure_installation : command not found 

Is mysql_secure not installed on ubuntu 16.04 - 64bit, with mysql-server-core-5.7 ?

How can I get it ?

It seems that I missed one step in the install. This page helped me identifying the missing step

I've double check it, and installed it on Ubuntu 16.04, and saw that it worked.

The full steps are:

1. update your system

   sudo apt update
   sudo apt upgrade
   

2. Install both - mysql client & server

   sudo apt install mysql-server mysql-client
   

Note: You need to type the password for the MySQL root user:

3. Run mysql_secure_installation to secure your installation

   sudo mysql_secure_installation