Update ssh-keys.md

docs.it4i/general/accessing-the-clusters/shell-access-and-data-transfer/ssh-keys.md

@@ -14,6 +14,26 @@ local $ ssh-keygen -C 'username@organization.example.com' -f additional_key
 By default, your private key is saved to the `id_rsa` file in the `.ssh` directory
 and your public key is saved to the `id_rsa.pub` file.
 
+## Adding SSH Key to your linux system SSH Agent
+
+1. Check if SSH Agent is running:
+
+    ```
+    eval "$(ssh-agent -s)"
+    ```
+
+1. Add the key to SSH Agent:
+
+    ```
+    ssh-add ~/.ssh/name_of_your_ssh_key_file
+    ```
+
+1.  Verify the key Added to SSH Agent:
+
+    ```
+    ssh-add -l
+    ```
+
 ## Managing Your SSH Key
 
 To manage your SSH key for authentication to clusters, see the [SSH Key Management][1] section.