安装Homebrew
Homebrew是Mac OSX下一个包依赖管理工具，用它来安装软件非常的方便只需要brew install 软件名这一条命令就可以将你所需要的软件安装好，不用再操心安装过程中软件的依赖问题，这些问题Homebrew统统帮你搞定，Homebrew的官网：http://brew.sh/ 在官网上对Homebrew的安装和用法有详细的描述这里就不多扯了。如果你还没有安装，还等什么赶紧动手安装吧！:]
Homebrew安装方法也很简单：打开终端，然后输入命令
ruby -e "$(curl -fsSL https://raw.github.com/mxcl/homebrew/go)"
对，就是这么简单一条命令就可以将神器Homebrew安装好.
安装MongoDB
MongoDB是一个基于分布式文件存储的数据库。由C++语言编写。旨在为WEB应用提供可扩展的高性能数据存储解决方案。 MongoDB是一个介于关系数据库和非关系数据库之间的产品，是非关系数据库当中功能最丰富，最像关系数据库的。他支持的数据结构非常松散，是类似json的bson格式，因此可以存储比较复杂的数据类型。Mongo最大的特点是他支持的查询语言非常强大，其语法有点类似于面向对象的查询语言，几乎可以实现类似关系数据库单表查询的绝大部分功能，而且还支持对数据建立索引.
进入正题开始用Homebrew安装主角MongoDB～～～
在终端输入如下命令即可安装MongoDB
brew install mongodb
用Homebrew安装软件是不是很爽，耐心等待一会儿MongoDB就会安装好了……
测试MongoDB是否安装成功
在终端输入如下命令进行测试
mongod
mongod命令是用来启动MongoDB的服务的
执行mongos命令后返回了一堆错误信息，如下：
mongod --help for help and startup options
2014-07-17T21:34:21.732+0800 [initandlisten] MongoDB starting : pid=13117 port=27017 dbpath=/data/db 64-bit host=zhcmacbook-pro.local
2014-07-17T21:34:21.732+0800 [initandlisten] db version v2.6.3
2014-07-17T21:34:21.732+0800 [initandlisten] git version: nogitversion
2014-07-17T21:34:21.732+0800 [initandlisten] build info: Darwin minimavericks.local 13.2.0 Darwin Kernel Version 13.2.0: Thu Apr 17 23:03:13 PDT 2014; root:xnu-2422.100.13~1/ RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49
2014-07-17T21:34:21.732+0800 [initandlisten] allocator: tcmalloc
2014-07-17T21:34:21.732+0800 [initandlisten] options: {}
2014-07-17T21:34:21.733+0800 [initandlisten] exception in initAndListen: 10296
*********************************************************************
ERROR: dbpath (/data/db) does not exist.
Create this directory or give existing directory in --dbpath.
See http://dochub.mongodb.org/core/startingandstoppingmongo
*********************************************************************
, terminating
2014-07-17T21:34:21.733+0800 [initandlisten] dbexit:
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: going to close listening sockets...
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: going to flush diaglog...
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: going to close sockets...
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: waiting for fs preallocator...
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: lock for final commit...
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: final commit...
2014-07-17T21:34:21.733+0800 [initandlisten] shutdown: closing all files...
2014-07-17T21:34:21.733+0800 [initandlisten] closeAllFiles() finished
2014-07-17T21:34:21.733+0800 [initandlisten] dbexit: really exiting now
这么一堆错误信息，重点是这几句
ERROR: dbpath (/data/db) does not exist. Create this directory or give existing directory in –dbpath. See http://dochub.mongodb.org/core/startingandstoppingmongo
错误信息的意思是dbpath (/data/db)不存在，需要创建/data/db这个目录或者使用--dbpath参数项指定一个已经存在的目录。
dbpath (/data/db)这个目录是用来存储MongoDB数据文件的地方
既然不存在/data/db那我们就创建这个目录
首先在终端输入cd /命令返回到磁盘根目录
然后输入mkdir -p /data/db创建/data/db
再次输入mongos命令启动MongoDB的服务，服务又退出了返回一堆信息如下：
mongod --help for help and startup options
2014-07-17T23:56:40.285+0800 [initandlisten] MongoDB starting : pid=21182 port=27017 dbpath=/data/db 64-bit host=zhcmacbook-pro.local
2014-07-17T23:56:40.285+0800 [initandlisten] db version v2.6.3
2014-07-17T23:56:40.285+0800 [initandlisten] git version: nogitversion
2014-07-17T23:56:40.285+0800 [initandlisten] build info: Darwin minimavericks.local 13.2.0 Darwin Kernel Version 13.2.0: Thu Apr 17 23:03:13 PDT 2014; root:xnu-2422.100.13~1/ RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49
2014-07-17T23:56:40.285+0800 [initandlisten] allocator: tcmalloc
2014-07-17T23:56:40.285+0800 [initandlisten] options: {}
2014-07-17T23:56:40.287+0800 [initandlisten] exception in initAndListen: 10309 Unable to create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating
2014-07-17T23:56:40.287+0800 [initandlisten] dbexit:
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: going to close listening sockets...
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: going to flush diaglog...
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: going to close sockets...
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: waiting for fs preallocator...
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: lock for final commit...
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: final commit...
2014-07-17T23:56:40.287+0800 [initandlisten] shutdown: closing all files...
2014-07-17T23:56:40.288+0800 [initandlisten] closeAllFiles() finished
2014-07-17T23:56:40.288+0800 [initandlisten] shutdown: removing fs lock...
2014-07-17T23:56:40.288+0800 [initandlisten] couldn't remove fs lock errno:9 Bad file descriptor
2014-07-17T23:56:40.288+0800 [initandlisten] dbexit: really exiting now
出错原因是这几句log
create/open lock file: /data/db/mongod.lock errno:13 Permission denied Is a mongod instance already running?, terminating
意思是不创建和打开/data/db/mongod.lock这个文件，原因是Permission denied（权限拒绝），看来是当前用户执行mongod这个命令时，对/data/db这个目录没有操作权限，OK，知道原因就好办了，给/data/db加上权限。
在终端输入如下命令：
sudo chown -R 当前登录的用户名 /data
再次在终端输入mongod启动MongoDB的服务，返回如下信息：
mongod --help for help and startup options
2014-07-18T01:29:23.286+0800 [initandlisten] MongoDB starting : pid=22420 port=27017 dbpath=/data/db 64-bit host=zhcmacbook-pro.local
2014-07-18T01:29:23.286+0800 [initandlisten] db version v2.6.3
2014-07-18T01:29:23.286+0800 [initandlisten] git version: nogitversion
2014-07-18T01:29:23.286+0800 [initandlisten] build info: Darwin minimavericks.local 13.2.0 Darwin Kernel Version 13.2.0: Thu Apr 17 23:03:13 PDT 2014; root:xnu-2422.100.13~1/ RELEASE_X86_64 x86_64 BOOST_LIB_VERSION=1_49
2014-07-18T01:29:23.286+0800 [initandlisten] allocator: tcmalloc
2014-07-18T01:29:23.287+0800 [initandlisten] options: {}
2014-07-18T01:29:23.288+0800 [initandlisten] journal dir=/data/db/journal
2014-07-18T01:29:23.288+0800 [initandlisten] recover : no journal files present, no recovery needed
2014-07-18T01:29:23.437+0800 [initandlisten] waiting for connections on port 27017
终于启动成功了，然后再打开一个新的终端窗口输入mongo命令，返回如下信息：
MongoDB shell version: 2.6.3
connecting to: test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
http://docs.mongodb.org/
Questions? Try the support group
http://groups.google.com/group/mongodb-user
>
export PATH=${PATH}:/Users/liubo/Documents/mongodb-osx-x86_64-2.4.3/bin/
哦耶！，成功进入MongoDB的命令行模式，到这里MongoDB就安装好了！:] :] :]……
