Password-less SSH

ssh-keygen -t rsa


#################################################################
#the message will like the following text
#################################################################

#Generating public/private rsa key pair.
#Enter file in which to save the key (/home/skx/.ssh/id_rsa): 
#Enter passphrase (empty for no passphrase): 
#Enter same passphrase again: 
#Your identification has been saved in /home/skx/.ssh/id_rsa.
#Your public key has been saved in /home/skx/.ssh/id_rsa.pub.


ssh-copy-id -i ~/.ssh/id_rsa.pub ${username}@${IP}

Reference: Debian Administration