Generating a new SSH key

1-Open Terminal.

2-Paste the text below, substituting in your GitHub email address.

$ ssh-keygen -t rsa -b 4096 -C "your_email@example.com"

This creates a new ssh key, using the provided email as a label.

> Generating public/private rsa key pair.

3-When you're prompted to "Enter a file in which to save the key," press Enter. This accepts the default file location.

> Enter a file in which to save the key (/home/you/.ssh/id_rsa): [Press enter]

4-At the prompt, type a secure passphrase. For more information, see "Working with SSH key passphrases".

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

Adding your SSH key to the ssh-agent

Before adding a new SSH key to the ssh-agent to manage your keys, you should have checked for existing SSH keys and generated a new SSH key.

1-Start the ssh-agent in the background.

$ eval "$(ssh-agent -s)"
> Agent pid 59566

2-Add your SSH private key to the ssh-agent. If you created your key with a different name, or if you are adding an existing key that has a different name, replace id_rsa in the command with the name of your private key file.

$ ssh-add ~/.ssh/id_rsa

Adding SSH key for windows

1. Move to user/username/.ssh.

2. First time use (authorizor mode in windows powershell).

Set-Service -Name ssh-agent -StartupType Automatic
Start-Service ssh-agent
Get-Service ssh-agent

3. Start ssh-agent in the background.

ssh-agent | Out-String
ssh-add ./private_key

Adding a new SSH key to your GitHub account

To configure your GitHub account to use your new (or existing) SSH key, you'll also need to add it to your GitHub account.

1-Copy the SSH key to your clipboard.

If your SSH key file has a different name than the example code, modify the filename to match your current setup. When copying your key, don't add any newlines or whitespace.

$ sudo apt-get install xclip
# Downloads and installs xclip. If you don't have `apt-get`, you might need to use another installer (like `yum`)

$ xclip -sel clip < ~/.ssh/id_rsa.pub
# Copies the contents of the id_rsa.pub file to your clipboard

2-In the upper-right corner of any page, click your profile photo, then click Settings. 

3-In the user settings sidebar, click SSH and GPG keys. 

4-Click New SSH key or Add SSH key.

5-In the "Title" field, add a descriptive label for the new key. For example, if you're using a personal Mac, you might call this key "Personal MacBook Air".

6-Paste your key into the "Key" field. 

7-Click Add SSH key.