To access command history you just need to use your up and down arrow keys or look for the content of the file ~/.bash_history
i run
[root@server]# mysql_secure_installation
and after i run
[root@server]# reset-mysql-root-password YOURPASSWORDHERE
now i am able to see the password by access to the last inputs in the command line, using the arrow key "up"
to see the password in the file ~/.bash_history i need to exit from root and login again.
[root@server]# exit
[root@server]# su -
[root@server]# vim ~/.bash_history
Now i can confirm that the password is visible in this file and i erase this line from the file

After i close and save the file i have to exit from root and login again to confirm that
reset-mysql-root-password YOURPASSWORDHERE is not accessible anymore from the command line history by using the arrow key "up" to walk in the last inputs we have done in the command line.
OK.. I confess,
I am paranoid about security 8-)