mac下用git操作（push、pull）过程及注意事项

1、安装git：http://git-scm.com/download/
2、检查是否已经存在ssh （命令：$cd ～/.ssh）

   如果存在，先将已有的ssh备份，或者将新建的ssh生成到另外的目录下
   如果不存在，通过默认的参数直接生成ssh
   生成过程如下：
   $ssh-keygen -t rsa -C xxxxx@gmail.com（注册github时的email）（注意空格）
    Generating public/private rsa key pair.
    Enter file in which to save the key (/Users/twer/.ssh/id_rsa): 
    Created directory '/Users/twer/.ssh'.
    Enter passphrase (empty for no passphrase): 
    Enter same passphrase again: 
    Your identification has been saved in /Users/twer/.ssh/id_rsa.
    Your public key has been saved in /Users/twer/.ssh/id_rsa.pub.
    The key fingerprint is:
    18:16:11:c9:01:6c:48:09:7f:27:c6:43:0d:7f:3f:84 xxxxx@gmail.com
    The key's randomart image is:
    +--[ RSA 2048]----+
    |.o.++===         |
    |.ooo.+. .       |
    |  ..* = E .      |
    |   o = + o       |
    |      . S o      |
    |           .     |
    |                 |
    |                 |
    |                 |
   +-----------------+

3、 在github中添加ssh：

   登陆github，选择Settings-->SSH Keys 添加ssh
   Title：xxxxx@gmail.com
   Key：打开你生成的id_rsa.pub文件，将其中内容拷贝至此（路径在第2步）

4、测试SSH：

   $ssh git@github.com
   The authenticity of host 'github.com (207.97.227.239)' can't be established.
   RSA key fingerprint is 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48.
   Are you sure you want to continue connecting (yes/no)? **yes**
   Warning: Permanently added 'github.com,207.97.227.239' (RSA) to the list of known hosts.
   PTY allocation request failed on channel 0
   Hi xianfuying! You've successfully authenticated, but GitHub does not provide shell access.
            Connection to github.com closed.
   设置本地git个人信息：
   $git config --global user.name "github用户名"
   $git config --global user.email "注册邮箱"

5、将本地代码push到github

   先在github中创建Repository：
   https://github.com/ --> New Repository 输入Repository信息 projectName
   在本地创建代码库：              
   $mkdir test   //创建一个文件夹作为local repositor
   $cd test     
   $vi test.txt  //创建一个文件(代码？)
   $git add test.txt //将文件添加至local repository
   $git init    //初始化local repository
   $git commit -m "first" //commit文件 不能为空否则会出错（“commit -a” 又没有添加说明会出错）
   git remote add origin https://github.com/用户名/projectName.git 
   //定义远程服务器别名(origin可随便取)但不能重复 若为重复错误 可rm别名重新定义：git remote rm origin
   $git push -u origin master//将本地数据push到github上

6、从github中pull代码：

  使用命令：
  $git pull https://github.com/用户名/项目名  //将github上的代码pull到local repository中