Add ssh user to a Linux (ubuntu/Debian) server, that only has ssh key access
Procedure adapted from https://unix.stackexchange.com/questions/210228/add-a-user-wthout-password-but-with-ssh-and-public-key
create a variable with username
export username='tom'
create the user and add public key to authorized_keys file
sudo useradd -m -d /home/$username -s /bin/bash $username sudo mkdir /home/$username/.ssh sudo vim /home/$username/.ssh/authorized_keys
fix permisions for file and directory
sudo chown -R $username:$username /home/$username/.ssh sudo chmod 700 /home/$username/.ssh sudo chmod 600 /home/$username/.ssh/authorized_keys
if sudo required add user to the group
sudo usermod -aG sudo $username
...