터치바 맥북으로 갈아타면서 새로운 기능이 몇가지 있는데 생소해서 기록 ㅎㅎㅎ

자동부팅 활성 : sudo nvram BootAudio=%03

자동부팅 비활성 : sudo nvram BootAudio=%00

How to restore the classic Mac startup chime to Apple’s new 2016 MacBook Pros

By Neil Hughes
Monday, October 31, 2016, 08:50 am PT (11:50 am ET)
Apple’s newly released MacBook Pros do away with the classic F-sharp major boot-up chime that has been a part of the Mac since 1999. Thankfully, for those who want to keep it, there’s an easy way to bring it back.

In addition to ditching the startup chime, Apple’s new MacBook Pros with Touch Bar automatically boot up when plugged into power or when the lid is opened. But now, they do so silently, without the chime Mac users have grown accustomed to over the last 17 years.

While it’s off by default, it’s not gone entirely. A simple Terminal command spotlighted by Pingie can bring it back.

Simply open Terminal in macOS and type the following command:

sudo nvram BootAudio=%01

It should be noted that making such modifications to your system requires a user to enter their administrative password. If you want to return to the new, silent boot mode, the change can be reversed with the following Terminal command:

sudo nvram BootAudio=%00

The new auto-boot configuration when plugged in or opened can also be disabled if a user wants to return their Mac to a more familiar state. The “AutoBoot” functionality can be disabled with the following command in Terminal:

sudo nvram AutoBoot=%00

Likewise, the auto-boot functionality can be restored with yet another simple command. It is:

sudo nvram AutoBoot=%03

The current but outgoing Mac chime was first introduced on the iMac G3 in 1999. Prior to that, various versions of the chime have been a staple of the Mac since the Macintosh II.