不知道为什么没有人提到这一点:当你从官方网站运行安装命令时，在最后几行你会看到如下内容，你需要遵循==>下一步:

==> Installation successful!

==> Homebrew has enabled anonymous aggregate formulae and cask analytics.
Read the analytics documentation (and how to opt-out) here:
  https://docs.brew.sh/Analytics
No analytics data has been sent yet (or will be during this `install` run).

==> Homebrew is run entirely by unpaid volunteers. Please consider donating:
  https://github.com/Homebrew/brew#donations

==> Next steps:
- Add Homebrew to your PATH in /Users/{YOUR USER NAME}/.bash_profile:
    echo 'eval $(/opt/homebrew/bin/brew shellenv)' >> /Users/{YOUR USER NAME}/.bash_profile
    eval $(/opt/homebrew/bin/brew shellenv)

这是bash shell的。对于每个不同的shell，您将看到不同的步骤，但是这些步骤的源是相同的。

在一个开箱即用的MacOS High Sierra 10.13.6

$ ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"

给出以下错误:

curl performs SSL certificate verification by default, using a "bundle" of Certificate Authority (CA) public keys (CA certs). If the default bundle file isn't adequate, you can specify an alternate file using the --cacert option. If this HTTPS server uses a certificate signed by a CA represented in the bundle, the certificate verification probably failed due to a problem with the certificate (it might be expired, or the name might not match the domain name in the URL). If you'd like to turn off curl's verification of the certificate, use the -k (or --insecure) option. HTTPS-proxy has similar options --proxy-cacert and --proxy-insecure.

解决方案:只要在你的卷曲选项中添加一个k

$ ruby -e "$(curl -fsSLk https://raw.githubusercontent.com/Homebrew/install/master/install)"

如果你使用的是m1芯片mac，那么在安装homebrew后运行以下命令并再次打开终端:

echo "export PATH=/opt/homebrew/bin:$PATH" >> ~/.zshrc

对我有用的是设置BREW_FILE_DIRECTORY，如下所示

echo "export BREW_FILE_DIRECTORY=/opt" >> ~/.zshrc .

因为brew.sh文件在/opt/homebrew/bin下 在脚本中，所有内容似乎都是从BREW_FILE_DIRECTORY变量计算出来的。这在MacBook Pro (M1)上是可行的

我在mac BigSur M1处理器上安装Homebrew时遇到了同样的brew命令找不到的问题。

I -安装XCode，如果它还没有安装。

II -选择终端。应用程序在Finder。

III -人民币点击终端，选择“获取信息”

IV -选中“使用Rosetta打开”复选框。

关闭所有打开的终端窗口。

打开一个新的终端窗口，安装Hobebrew:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install.sh)"

测试自制软件的安装。

IIX -取消勾选使用Rosetta打开复选框。

下面是一个将自制程序安装程序包装在bash函数中的版本，可以从部署脚本中运行:

install_homebrew_if_not_present() {
    echo "Checking for homebrew installation"
    which -s brew
    if [[ $? != 0 ]] ; then
        echo "Homebrew not found. Installing..."
        ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
    else
        echo "Homebrew already installed! Updating..."
        brew update
    fi
}

另一个函数将安装一个自制公式，如果它还没有安装:

brew_install () {       
    if brew ls --versions $1 > /dev/null; then
        echo "already installed: $1"
    else
        echo "Installing forumula: $1..."
        brew install $1
    fi
}

一旦你定义了这些函数，你可以在你的bash脚本中像下面这样使用它们:

install_homebrew_if_not_present
brew_install wget
brew_install openssl
...