这算是为了安装php扩展做的准备工作吧：
1. cd /usr/lib/php
2. sudo php install-pear-nozlib.phar
[PEAR] Archive_Tar - installed: 1.3.11
[PEAR] Console_Getopt - installed: 1.3.1
warning: pear/PEAR requires package "pear/Structures_Graph" (recommended version 1.0.4)
warning: pear/PEAR requires package "pear/XML_Util" (recommended version 1.2.1)
[PEAR] PEAR - installed: 1.9.4
Wrote PEAR system config file at: /usr/local/etc/php/5.6/pear.conf
You may want to add: /usr/local/Cellar/php56/5.6.23/lib/php/pear to your php.ini include_path
[PEAR] Structures_Graph- installed: 1.0.4
[PEAR] XML_Util - installed: 1.2.1
然后，编辑php.ini文件
vi /usr/local/etc/php/5.6/php.ini
将其中的include_path改为：
include_path = ".:/usr/local/Cellar/php56/5.6.23/lib/php/pear"
然后，执行命令：
sudo pear channel-update pear.php.net
sudo pecl channel-update pecl.php.net
sudo pear upgrade-all
即可。