配置SSH Keys到github，实现git clone 能力

问题：在机器没有配置git ssh keys 的时候，会出现一个错误：

Permission denied (publickey). fatal: The remote end hung up unexpectedly

配置步骤如下

Step 1: Check for SSH keys

First, we need to check for existing ssh keys on your computer. Open up Terminal and run:

cd ~/.ssh
ls
# Lists the files in your .ssh directory

Check the directory listing to see if you have a file named either id_rsa.pub or id_dsa.pub. If you don't have either of those files go to step 2. Otherwise, you already have an existing keypair, and you can skip to step 3.

Step 2: Generate a new SSH key

To generate a new SSH key, enter the code below. We want the default settings so when asked to enter a file in which to save the key, just press enter.

ssh-keygen -t rsa -C "[email protected]"
# Creates a new ssh key, using the provided email as a label
# Generating public/private rsa key pair.
# Enter file in which to save the key (/Users/you/.ssh/id_rsa): [Press enter]
ssh-add id_rsa

Now you need to enter a passphrase.

Why do passphrases matter?

# Enter passphrase (empty for no passphrase): [Type a passphrase]
# Enter same passphrase again: [Type passphrase again]

Which should give you something like this:

# Your identification has been saved in /Users/you/.ssh/id_rsa.
# Your public key has been saved in /Users/you/.ssh/id_rsa.pub.
# The key fingerprint is:
# 01:0f:f4:3b:ca:85:d6:17:a1:7d:f0:68:9d:f0:a2:db [email protected]

Step 3: Add your SSH key to GitHub

Run the following code to copy the key to your clipboard.

pbcopy < ~/.ssh/id_rsa.pub
# Copies the contents of the id_rsa.pub file to your clipboard

Alternatively, using your favorite text editor, you can open the ~/.ssh/id_rsa.pub file and copy the contents of the file manually

Warning: it's important to copy the key exactly without adding newlines or whitespace. Thankfully the pbcopycommand makes it easy to perform this setup perfectly.

1. Go to your Account Settings
2. Click "SSH Keys" in the left sidebar
3. Click "Add SSH key"
4. Paste your key into the "Key" field
5. Click "Add key"
6. Confirm the action by entering your GitHub password

Step 4: Test everything out

To make sure everything is working you'll now SSH to GitHub. When you do this, you will be asked to authenticate this action using your password, which for this purpose is the passphrase you created earlier. Don't change the [email protected] part. That's supposed to be there.

ssh -T [email protected]
# Attempts to ssh to github

You may see this warning:

# 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)?

Don't worry, this is supposed to happen. Verify that the fingerprint matches the one here and type "yes".

# Hi username! You've successfully authenticated, but GitHub does not
# provide shell access.

If that username is correct, you've successfully set up your SSH key. Don't worry about the shell access thing, you don't want that anyway.

If you see "access denied" please consider using HTTPS instead of SSH. If you need SSH start atthese instructions for diagnosing the issue.