How to log in without entering a password SSH

Want to go from a@HostA ssh to b@HostB without entering a password

This requires the use of a key

First of all, you need a key pair, do not enter passphrase. (if it has been generated before, you can use it directly.)

Ajar rsaGenerating public/private rsa key pair.Enter file in which to save the key ~ > ssh-keygen-t rsaGenerating public/private rsa key pair.Enter file in which to save the key (/ home/a/.ssh/id_rsa): Created directory'/ home/a/.ssh'.Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in / home/a/.ssh/id_rsa.Your public key has been saved in / home/a/.ssh/id_rsa.pub.The key fingerprint is:3e:4f:05:79:3a: 9f:96:7c:3b:ad:e9:58:37:bc:37:e4 aura

two。 The private key file is placed in the user a@HostA 's ~ / .ssh/id_rsa file, which is also the default location of the ssh-keygen generation file

3. Add the contents of the public key to the .ssh / authorized_keys file of b@HostB

Done!