本文主要解决一个问题
git clone 出现公共密钥的权限问题。症状如下：
CasondeMacBook-Pro:devops cason$ git clone git@github.com:360yyou/yyou.git
Cloning into 'yyou'...
Permission denied (publickey).
fatal: Could not read from remote repository.
Please make sure you have the correct access rights
and the repository exists.
要debug这个问题，可以用 ssh －vT 参数，比如下面：
ssh -vT git@github.com
OpenSSH_6.2p2, OSSLShim 0.9.8r 8 Dec 2011
debug1: Reading configuration data /etc/ssh_config
debug1: /etc/ssh_config line 20: Applying options for *
debug1: /etc/ssh_config line 102: Applying options for *
debug1: Connecting to github.com [192.30.252.130] port 22.
debug1: Connection established.
debug1: identity file /Users/cason/.ssh/id_rsa type -1
debug1: identity file /Users/cason/.ssh/id_rsa-cert type -1
debug1: identity file /Users/cason/.ssh/id_dsa type -1
debug1: identity file /Users/cason/.ssh/id_dsa-cert type -1
debug1: Enabling compatibility mode for protocol 2.0
debug1: Local version string SSH-2.0-OpenSSH_6.2
debug1: Remote protocol version 2.0, remote software version libssh-0.7.0
debug1: no match: libssh-0.7.0
debug1: SSH2_MSG_KEXINIT sent
debug1: SSH2_MSG_KEXINIT received
debug1: kex: server->client aes128-ctr hmac-sha1 none
debug1: kex: client->server aes128-ctr hmac-sha1 none
debug1: sending SSH2_MSG_KEXDH_INIT
debug1: expecting SSH2_MSG_KEXDH_REPLY
debug1: Server host key: RSA 16:27:ac:a5:76:28:2d:36:63:1b:56:4d:eb:df:a6:48
debug1: Host 'github.com' is known and matches the RSA host key.
debug1: Found key in /Users/cason/.ssh/known_hosts:2
Warning: Permanently added the RSA host key for IP address '192.30.252.130' to the list of known hosts.
debug1: ssh_rsa_verify: signature correct
debug1: SSH2_MSG_NEWKEYS sent
debug1: expecting SSH2_MSG_NEWKEYS
debug1: SSH2_MSG_NEWKEYS received
debug1: Roaming not allowed by server
debug1: SSH2_MSG_SERVICE_REQUEST sent
debug1: SSH2_MSG_SERVICE_ACCEPT received
debug1: Authentications that can continue: publickey
debug1: Next authentication method: publickey
debug1: Trying private key: /Users/cason/.ssh/id_rsa
debug1: Trying private key: /Users/cason/.ssh/id_dsa
debug1: No more authentication methods to try.
Permission denied (publickey).
解决方案：
首先要设置你的系统的公共，私有密钥（ssh-keygen)
方法：
cd ~/.ssh && ssh-keygen
其次，把公共密钥放置到github上，可以通过剪贴板来做这事
On OSX run: cat id_rsa.pub | pbcopy
On Linux run: cat id_rsa.pub | xclip
最后，设置你的git
git config --global user.name "bob"
git config --global user.email bob@...