SSH UBUNTU GIT

config

Assuming you are connecting GitHub over SSH, you can run below command to confirm this.

$git config --get remote.origin.url
If you get a result has following format git@github.com:xxx/xxx.github.com.git, then you should do the following.

Generate a SSH key(or use existing one). if you had one, you just need to add your key to the ssh-agent (step 2)and to your GitHub account(step 3).

below are for those who don't have SSH key.

Step 1 Generating public/private rsa key pair.

$ssh-keygen -t rsa -b 4096 -C "your_email@example.com"
You'll be asked to confirm where to save the SSH key and what passphrase you want to use.

Step 2 Add your key to the ssh-agent

Ensure ssh-agent is enabled

$eval "$(ssh-agent -s)"

Add your SSH key to the ssh-agent:

$ssh-add ~/.ssh/id_rsa

Step 3 Add your SSH key to your account

$sudo apt-get install xclip

$xclip -sel clip < ~/.ssh/id_rsa.pub

Then add the copied key to GitHub

Go to Settings->SSH keys(Personal settings side bar)->Add SSH key->fill out form(key is on your clipboard, just use ctrl+v)->Add key

After going through above steps, you should solve the permission problem.

Reference Link: Generating SSH keys.