Ssh Linux

This configuration starts by creating a pair of keys and handling them on linux.
This is good also for tasks like connecting to a remote machine in the cloud.
At the end, we also go through using this for github (so adding the public key to a github account).

Add SSH key

• To work with github or connecting to a remote server we normally need to use SSH keys.
• We start by creating a pair of keys, as in the following example:

1ssh-keygen -t ed25519 -C "yuval.shaul@gmail.com"

• The email address at the end is just a comment you attach to the public key.
• -t ed25519 is the key type
• The response:

1Generating public/private ed25519 key pair.

• Now I can change the key name if I wish (I leave this blank to use the default name)

1Enter file in which to save the key (/home/yuval/.ssh/id_ed25519):

• I left everything else empty
• To verify:

1**ls ~/.ssh**

Make the key read only

If I skip this step - my key will not work.

1yuval@comp> chmod 400 id_ed25519
2yuval@comp> ls -l id_ed25519
3-r-------- 1 yuval yuval 411 Nov  3 18:37 id_ed25519
4yuval@comp> 

Add keys to the ssh agent

You can read about the ssh agent here.

1# First command to run the ssh agent
2eval "$(ssh-agent -s)"
3# Next command to add a key to the agent (my key is called id_ed25519, and it is on ~/.ssh directory)
4ssh-add ~/.ssh/id_ed25519

Add the public key to github

Add the public key to github like this:

• Cat the public key:

1cat ~/.ssh/id_ed25519.pub

• Copy with your mouse
• Go to your account settings (top-right-settings)
• Click SSH and GPG keys.
• Click New SSH key.
• In the "Title" field, add a descriptive label for the new key.
• Select the type of key (authentication in out case)
• In the "Key" field, paste your public key (including the email part)
• Click Add SSH key.