authorized keys bulk set up

This is a simple bash one-liner distributing local public key to authorized_keys on multiple target machines.

While using SSH to access remote (virtual) machines, it’s great to use keys instead of passwords.

I often receive a long list of newly created machines. It is hard to track all passwords on the new machines, so I prefer to switch to keys the first day I start using them. This still requires typing in all the passwords, but this is done only once.

The following command line iterates over a set of machines IPs, adds them to known hosts, prompts for the password and installs the public key (so the password will not be used for next logins).

for i in 11 12 13 14 15 ; do cat ~/.ssh/id_rsa.pub | ssh 10.0.0.$i "mkdir .ssh ; cat > .ssh/authorized_keys ; chmod -R go-rwx .ssh" ; done

The script writes the current user’s public key to a new remote authorized_keys file, and sets it’s file permissions accordingly.