You can login to a Linux system without entering a password and here are 3 simple steps to set it up.
Step 1: Generate the authentication key
To generate private and public keys, run this on a local machine:
admin@local$ ssh-keygen Generating public/private rsa key pair. Enter file in which to save the key (/home/admin/.ssh/id_rsa):[Enter key] Enter passphrase (empty for no passphrase): [Press enter key] Enter same passphrase again: [Pess enter key] Your identification has been saved in /home/admin/.ssh/id_rsa. Your public key has been saved in /home/admin/.ssh/id_rsa.pub. The key fingerprint is: 33:b3:fe:af:95:95:18:11:31:d5:de:96:2f:f2:35:f9 admin@local
Step 2: Install the public key on server
SSH usually comes with an utility called ssh-copy-id that simply adds the contents of client’s ~/.ssh/id_rsa.pub to the server’s ~/.ssh/authorized_keys:
admin@local$ ssh-copy-id -i ~/.ssh/id_rsa.pub server admin@server's password: Now try logging into the machine, with "ssh 'server'", and check in: .ssh/authorized_keys to make sure we haven't added extra keys that you weren't expecting.
In case ssh-copy-id isn’t available, you can use scp or other file transfer method.
Step 3: Access
Now just access the server by typing:
admin@local$ ssh server
You should see something like this:
admin@local$ ssh server admin@server$
Or this, if you entered the passphrase:
admin@local$ ssh server Enter passphrase for key '/home/admin/.ssh/id_rsa': admin@server$