.安装Homebrew
Homebrew依赖于Apple包Xcode，因此请打开一个终端窗口并执行如下命令:
$ xcode-select --install
安装包有点大，请耐心等待
在不断出现的确认对话框中都单击OK按钮(根据网络连接的速度，这可能会花一些时间)。接下来安装Homebrew:
Homebrew的官网：https://brew.sh/
或者直接在命令行输入：
/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"这个命令可在Homebrew网站(http://brew.sh/)的首页找到。在curl -fsSL和URL之间，务必包含一个空格。
注意 这个命令中的-e 让Ruby(Homebrew就是使用这种编程语言编写的)执行下载的代码。除非来源是你信任的，否则不要运行这样的命令。
过程有点漫长，如下所示：
==> This script will install:
/usr/local/bin/brew
/usr/local/share/doc/homebrew
/usr/local/share/man/man1/brew.1
/usr/local/share/zsh/site-functions/_brew
/usr/local/etc/bash_completion.d/brew
/usr/local/Homebrew
Press RETURN to continue or any other key to abort
==> Downloading and installing Homebrew...
remote: Counting objects: 105991, done.
remote: Compressing objects: 100% (34/34), done.
remote: Total 105991 (delta 21), reused 36 (delta 18), pack-reused 105937
Receiving objects: 100% (105991/105991), 24.07 MiB | 13.00 KiB/s, done.
Resolving deltas: 100% (77327/77327), done.
From https://github.com/Homebrew/brew
* [new branch] master -> origin/master
* [new tag] 0.1 -> 0.1
* [new tag] 0.2 -> 0.2
* [new tag] 0.3 -> 0.3
* [new tag] 0.4 -> 0.4
* [new tag] 0.5 -> 0.5
* [new tag] 0.6 -> 0.6
* [new tag] 0.7 -> 0.7
* [new tag] 0.7.1 -> 0.7.1
* [new tag] 0.8 -> 0.8
* [new tag] 0.8.1 -> 0.8.1
* [new tag] 0.9 -> 0.9
* [new tag] 0.9.1 -> 0.9.1
* [new tag] 0.9.2 -> 0.9.2
* [new tag] 0.9.3 -> 0.9.3
* [new tag] 0.9.4 -> 0.9.4
* [new tag] 0.9.5 -> 0.9.5
* [new tag] 0.9.8 -> 0.9.8
* [new tag] 0.9.9 -> 0.9.9
* [new tag] 1.0.0 -> 1.0.0
* [new tag] 1.0.1 -> 1.0.1
* [new tag] 1.0.2 -> 1.0.2
* [new tag] 1.0.3 -> 1.0.3
* [new tag] 1.0.4 -> 1.0.4
* [new tag] 1.0.5 -> 1.0.5
* [new tag] 1.0.6 -> 1.0.6
* [new tag] 1.0.7 -> 1.0.7
* [new tag] 1.0.8 -> 1.0.8
* [new tag] 1.0.9 -> 1.0.9
* [new tag] 1.1.0 -> 1.1.0
* [new tag] 1.1.1 -> 1.1.1
* [new tag] 1.1.10 -> 1.1.10
* [new tag] 1.1.11 -> 1.1.11
* [new tag] 1.1.12 -> 1.1.12
* [new tag] 1.1.13 -> 1.1.13
* [new tag] 1.1.2 -> 1.1.2
* [new tag] 1.1.3 -> 1.1.3
* [new tag] 1.1.4 -> 1.1.4
* [new tag] 1.1.5 -> 1.1.5
* [new tag] 1.1.6 -> 1.1.6
* [new tag] 1.1.7 -> 1.1.7
* [new tag] 1.1.8 -> 1.1.8
* [new tag] 1.1.9 -> 1.1.9
* [new tag] 1.2.0 -> 1.2.0
* [new tag] 1.2.1 -> 1.2.1
* [new tag] 1.2.2 -> 1.2.2
* [new tag] 1.2.3 -> 1.2.3
* [new tag] 1.2.4 -> 1.2.4
* [new tag] 1.2.5 -> 1.2.5
* [new tag] 1.2.6 -> 1.2.6
* [new tag] 1.3.0 -> 1.3.0
* [new tag] 1.3.1 -> 1.3.1
* [new tag] 1.3.2 -> 1.3.2
* [new tag] 1.3.3 -> 1.3.3
* [new tag] 1.3.4 -> 1.3.4
* [new tag] 1.3.5 -> 1.3.5
* [new tag] 1.3.6 -> 1.3.6
* [new tag] 1.3.7 -> 1.3.7
* [new tag] 1.3.8 -> 1.3.8
* [new tag] 1.3.9 -> 1.3.9
* [new tag] 1.4.0 -> 1.4.0
* [new tag] 1.4.1 -> 1.4.1
* [new tag] 1.4.2 -> 1.4.2
* [new tag] 1.4.3 -> 1.4.3
* [new tag] 1.5.0 -> 1.5.0
* [new tag] 1.5.1 -> 1.5.1
* [new tag] 1.5.10 -> 1.5.10
* [new tag] 1.5.11 -> 1.5.11
* [new tag] 1.5.12 -> 1.5.12
* [new tag] 1.5.13 -> 1.5.13
* [new tag] 1.5.14 -> 1.5.14
* [new tag] 1.5.2 -> 1.5.2
* [new tag] 1.5.3 -> 1.5.3
* [new tag] 1.5.4 -> 1.5.4
* [new tag] 1.5.5 -> 1.5.5
* [new tag] 1.5.6 -> 1.5.6
* [new tag] 1.5.7 -> 1.5.7
* [new tag] 1.5.8 -> 1.5.8
* [new tag] 1.5.9 -> 1.5.9
* [new tag] 1.6.0 -> 1.6.0
* [new tag] 1.6.1 -> 1.6.1
* [new tag] 1.6.10 -> 1.6.10
* [new tag] 1.6.11 -> 1.6.11
* [new tag] 1.6.12 -> 1.6.12
* [new tag] 1.6.13 -> 1.6.13
* [new tag] 1.6.14 -> 1.6.14
* [new tag] 1.6.15 -> 1.6.15
* [new tag] 1.6.16 -> 1.6.16
* [new tag] 1.6.17 -> 1.6.17
* [new tag] 1.6.2 -> 1.6.2
* [new tag] 1.6.3 -> 1.6.3
* [new tag] 1.6.4 -> 1.6.4
* [new tag] 1.6.5 -> 1.6.5
* [new tag] 1.6.6 -> 1.6.6
* [new tag] 1.6.7 -> 1.6.7
* [new tag] 1.6.8 -> 1.6.8
* [new tag] 1.6.9 -> 1.6.9
* [new tag] 1.7.0 -> 1.7.0
* [new tag] 1.7.1 -> 1.7.1
HEAD is now at 3c3b05d45 Merge pull request #4564 from reitermarkus/not-a-cask-file-error
==> Tapping homebrew/core
Cloning into '/usr/local/Homebrew/Library/Taps/homebrew/homebrew-core'...
remote: Counting objects: 4807, done.
remote: Compressing objects: 100% (4590/4590), done.
remote: Total 4807 (delta 57), reused 862 (delta 26), pack-reused 0
Receiving objects: 100% (4807/4807), 3.90 MiB | 14.00 KiB/s, done.
Resolving deltas: 100% (57/57), done.
Tapped 2 commands and 4592 formulae (4,848 files, 12.2MB).
==> Cleaning up /Library/Caches/Homebrew...
==> Migrating /Library/Caches/Homebrew to /Users/liao/Library/Caches/Homebrew...
==> Deleting /Library/Caches/Homebrew...
Already up-to-date.
Warning: /usr/local/bin is not in your PATH.
==> Installation successful!
==> Homebrew has enabled anonymous aggregate user behaviour analytics.
Read the analytics documentation (and how to opt-out) here:
https://docs.brew.sh/Analytics.html
==> Next steps:
- Run `brew help` to get started
- Further documentation:
https://docs.brew.sh
为确认正确地安装了Homebrew，请执行如下命令:
$ brew doctor
如果输出Your system is ready to brew.
表明你可以使用Homebrew来安装Python包了。