cs444  16apr2026
name: 

How to set up Passwordless Login
 (there is a version of the commands on the class website; 
  this version is based on a shortened version by Martin Dinh
  at https://b7csTour.github.io/LongProject1/Servers.html ;
  modified to check out the server ahead of the upload - jhd)

Check if you already have preexisting SSH key
  on your laptop:
ls -al ~/.ssh/id_*.pub
If you do, you can skip next step and upload them, or back them up and generate a new key

If not, Open terminal and run the command
ssh-keygen -t ed25519
Press enter to accept the default file location and file name
Decide whether or not you want a keyphrase
Verify the process by running the command
ls ~/.ssh/id_*

Login to the server and see whether you have a pre-existing SSH public key
Login
Type: cd .ssh <enter> and ls -l <enter>

If not, exit and 
Copy the key to the server with the command below and enter your password when prompted
ssh-copy-id username@users.cs.umb.edu

If your machine does not have ssh-copy-id, use the below command
cat ~/.ssh/id_ed25519.pub | ssh username@users.cs.umb.edu "mkdir -p ~/.ssh && chmod 700 ~/.ssh && cat >> ~/.ssh/authorized_keys && chmod 600 ~/.ssh/authorized_keys"