Reset Mac user password via SSH

Make sure you have a corresponding id_rsa.pub or id_dsa.pub in your ~/.ssh directory.

When I had an id_rsa but not a corresponding id_rsa.pub, Mac OS X kept popping up the dialog and remember passowrd in my keychain did nothing.

cd ~/.ssh
ssh-keygen -y -f id_rsa > id_rsa.pub

generated the appropriate public key file for me.

If you already had your public file there (rename it to another name) and generate the public key again using the above command, you'll notice that the generated and the old one are not equal. Somehow the older versions of Mac OS X generated a public key that Lion does not like anymore, generating it again fixes that.

For the curious, the key is exactly the same, the part that changes is that there is no "comments" section after the key on the file any longer.

First, you create a public and private key (if you haven't done so already) on the machine from which you want to login:

ssh-keygen -t dsa

You only need to do this if there isn't already a ~/.ssh/id_dsa.pub file.

On Linux, there's the ssh-copy-id helper. On Mac, you need to copy the public key by hand:

• Copy the generated public key to the target machine:

  scp ~/.ssh/id_dsa.pub user@targetmachine:myPublicKey.pub

• Login to the target machine:

  ssh user@targetmachine

• Append the public key to the authorized keys:

  cat myPublicKey.pub >>.ssh/authorized_keys

• You can now delete the copied key:

  rm myPublicKey.pub

• Done. You should now be able to login to your target machine without the need to enter a password.