参考：http://brew.sh/index_zh-cn.html

以下是我的具体执行过程:

zcms-iMac:~ zcm$ ruby -e "$(curl -fsSL https://raw.github.com/Homebrew/homebrew/go/install)"
==> This script will install:
/usr/local/bin/brew
/usr/local/Library/...
/usr/local/share/man/man1/brew.1
==> The following directories will be made group writable:
/usr/local/.
/usr/local/bin
==> The following directories will have their group set to admin:
/usr/local/.
/usr/local/binPress RETURN to continue or any other key to abort
==> /usr/bin/sudo /bin/chmod g+rwx /usr/local/. /usr/local/bin
Password:
Sorry, try again.
Password:
==> /usr/bin/sudo /usr/bin/chgrp admin /usr/local/. /usr/local/bin
==> /usr/bin/sudo /bin/mkdir /Library/Caches/Homebrew
==> /usr/bin/sudo /bin/chmod g+rwx /Library/Caches/Homebrew
==> Installing the Command Line Tools (expect a GUI popup):
==> /usr/bin/sudo /usr/bin/xcode-select --install
xcode-select: note: install requested for command line developer tools
Press any key when the installation has completed.
==> Downloading and installing Homebrew...
remote: Counting objects: 194283, done.
remote: Compressing objects: 100% (52754/52754), done.
remote: Total 194283 (delta 140405), reused 194219 (delta 140356)
Receiving objects: 100% (194283/194283), 39.05 MiB | 259.00 KiB/s, done.
Resolving deltas: 100% (140405/140405), done.
From https://github.com/Homebrew/homebrew* [new branch]      master     -> origin/master
HEAD is now at 251605c youtube-dl: update 2014.08.27.1 bottle.
==> Installation successful!
==> Next steps
Run `brew doctor` before you install anything
Run `brew help` to get started
zcms-iMac:~ zcm$

安装完成！

接下来就可以用brew来安装软件了,如安装tree命令：brew install tree