mac每次启动都打开消息
Since 1984, Apple computers played an endearing sound when powered on. This tone became a cultural calling card for the platform, but with the rise of automatically-booting Macs in 2016, Apple decided to remove this feature. If you miss the chime, there is a way to turn it back on. Here’s how.
自1984年以来，Apple电脑在开机时发出悦耳的声音。 这种语气成为该平台的文化名片，但是随着2016年自动启动Mac的兴起，Apple决定删除此功能。 如果您错过了提示音，有一种方法可以将其重新打开。 这是如何做。
修改后的设置如何工作？ (How Does the Modified Setting Work?)
To turn the chime on, we have to modify a setting in your Mac’s NVRAM (short for Non-Volatile Random Access Memory) using a terminal command. It’s not as scary as it sounds, but here’s some background on what’s going on.
要打开提示音，我们必须使用终端命令来修改Mac的NVRAM(非易失性随机存取存储器的缩写)中的设置。 它并不像听起来那样令人恐惧，但是这里有一些背景信息。
In a Mac, NVRAM is a small amount of memory that stores computer-wide settings. It remembers these settings without power, so they’re accessible at startup and available between system restarts.
在Mac中，NVRAM是存储计算机范围设置的少量内存。 它可以记住这些设置而无需通电，因此在启动时可以访问它们，并且在系统重新启动之间可以使用它们。
With the commands below, we are changing a setting in NVRAM called “StartupMute” that tells the computer whether or not to emit the chime at startup. The ‘sudo’ command is necessary because ‘nvram’ is a powerful command that requires superuser permissions to use.
使用下面的命令，我们正在NVRAM中更改一个名为“ StartupMute”的设置，该设置告诉计算机在启动时是否发出提示音。 “ sudo”命令是必需的，因为“ nvram”是功能强大的命令，需要超级用户权限才能使用。
If you’re curious for more information about NVRAM—what it is, and what it does—check out this handy How-To Geek guide. Also, Apple has more info on startup tones and what they mean on its website.
如果您想了解有关NVRAM的更多信息(它是什么，它做什么)的信息， 请查阅此方便的How-To Geek指南 。 此外，Apple在其网站上提供了有关启动音及其含义的更多信息 。
如何启用Mac启动提示音 (How to Enable the Mac Startup Chime)
First, launch Spotlight Search by hitting Command + Space on your keyboard. You’ll see a large search bar pop up in the middle of your screen.
首先，通过点击键盘上的Command + Space启动Spotlight搜索 。 屏幕中间会弹出一个大型搜索栏。
Type terminal and then hit the Return key.
键入terminal ，然后按回车键。
This will launch the Terminal app. With its default settings, Terminal appears as a window with a black background.
这将启动终端应用程序 。 使用其默认设置，终端显示为黑色背景的窗口。
In the Terminal window, type sudo nvram StartupMute=%00and then hit the Return button.
在“终端”窗口中，键入sudo nvram StartupMute=%00 ，然后单击“返回”按钮。
It will ask you for your password. Type in your password and hit Return again.
它将要求您输入密码。 输入您的密码，然后再次单击“返回”。
Now restart your Mac and see if it works. The chime should be there.
现在，重新启动Mac，看看它是否有效。 钟应该在那里。
如何禁用Mac启动提示音 (How to Disable the Mac Startup Chime)
If you’re tired of hearing your startup chime and would like to disable it again, here’s how to do it.
如果您厌倦了听到启动提示音并想再次禁用它，请按以下步骤操作。
Launch Spotlight Search by hitting Command + Space on the keyboard. You will see a large search bar pop up in the middle of your screen.
通过点击键盘上的Command + Space启动Spotlight搜索。 屏幕中间会弹出一个大搜索栏。
Type terminal and hit Return.
输入terminal并点击Return。
This will launch the Terminal app. With its default settings, Terminal appears as a window with a black background.
这将启动终端应用程序。 使用其默认设置，终端显示为黑色背景的窗口。
In the Terminal window, type sudo nvram StartupMute=%01and hit the Return key.
在“终端”窗口中，键入sudo nvram StartupMute=%01并单击Return键。
If it asks you for your password, type it in and hit Return.
如果要求您输入密码，请输入密码，然后单击“返回”。
Now restart your Mac and see if it works. The chime should be turned off.
现在，重新启动Mac，看看它是否有效。 应关闭提示音。
翻译自: https://www.howtogeek.com/658569/how-to-turn-on-the-startup-chime-on-your-new-mac/
mac每次启动都打开消息