When I run a mysql command in a script, "Warning: Using a password on the command line interface can be insecure" is displayed

My name is Ito, and I'm an infrastructure engineer. Our company uses a script to back up our database every night. We often use MySQL version 5.5, but we had an opportunity to use 5.6, and when we did, we ran the script as usual, and got the message "Warning: Using a password on the command line interface can be insecure."