Auto login in remote machine
Sometimes, we would like to automatically login to remote machine without keying the password. It can be done by generating public/private key and stores the keys in the remote machine.
Steps:
1) Open a terminal, and type the following line in the local machine:
~$ ssh-keygen -t rsa -b 2048Output:
Generating public/private rsa key pair.Enter file in which to save the key (/Users/henry/.ssh/id_rsa): Enter passphrase (empty for no passphrase): Enter same passphrase again: Your identification has been saved in /Users/henry/.ssh/id_rsa.Your public key has been saved in /Users/henry/.ssh/id_rsa.pub.The key fingerprint is: xxx2) Then type the following to copy the keys in the remote machine
~$ ssh-copy-d user@server_ipOutput:
/usr/bin/ssh-copy-id: INFO: Source of key(s) to be installed: "/Users/userid/.ssh/id_rsa.pub"/usr/bin/ssh-copy-id: INFO: attempting to log in with the new key(s), to filter out any that are already installed/usr/bin/ssh-copy-id: INFO: 1 key(s) remain to be installed -- if you are prompted now it is to install the new keysuser@server_ip's password: Key in the password
Number of key(s) added: 1Now try logging into the machine, with: "ssh 'user@server_ip'"and check to make sure that only the key(s) you wanted were added.3) Now we can login to the remote machine without key in the password.
To automatically ask a remote machine to run a script
Let's say we would like to run the command "last > dump.txt" at remote machine "server_ip", type the following command:
~$ ssh user@server_ip "last > dump.txt"