Use terminal commands to turn off the Mac computer startup tone

Mac users know that every time the computer is turned on or restarted, there will be a very special boot tone. If you want to temporarily prohibit the start-up tone, one way is to always hold down the keyboard mute button, of course you can also use the following method of using terminal commands:
By Spotlight Search and open the [terminal] program, then enter the following command and return, to disable the boot tone:

sudo nvram systemaudiovolume=%80

We will then need to enter the administrator password. This will then be completely muted when you start the Mac again.
If you want to restore the normal settings, then enter the following command again in the terminal:

sudo nvram-d systemaudiovolume

Use terminal commands to turn off the Mac computer startup tone