git의 몇 가지 일반적인 오류 요약

$ git push -u origin master
To git@github.com:xxx/xxx.git
 ! [rejected]        master -> master (fetch first)error: failed to push some refs to 'git@github.com:xxx/xxx.git'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

1. 查看秘钥是否存在

打开终端查看是否已经存在SSH密钥：cd ~/.ssh如果没有密钥则不会有此文件夹，有则备份删除,   也可以直接删除,  

2.生成新的秘钥, 命令如下

$ssh-keygen -t rsa -C "youremail@example.com"你需要把邮件地址换成你自己的邮件地址，然后一路回车，使用默认值即可，因为这个Key仅仅用于简单的服务，所以也无需设置密码。

完成后会有如下显示

Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /Users/你的电脑用户名/.ssh/id_rsa.
Your public key has been saved in /Users/你的电脑用户名/.ssh/id_rsa.pub.
The key fingerprint is:SHA256:5V6ZCQNS/3bVdl0GjGgQpWMFLazxTslnKbW2B1mbC+E example@qq.com如果服务器端需要公钥,  直接把.ssh目录下的id_rsa.pub配置即可, id_rsa为私钥一定要保密!!!!