To remove an SSH known host on Mac OS X, you will need to edit the known_hosts file, which is located in the .ssh directory in your home directory. This file contains a list of all the SSH servers that you have connected to from your Mac, along with the server's public host key.
To remove an entry from the known_hosts file, you will need to open the file in a text editor such as TextEdit or Nano. You can do this by using the following command:
refer to:lautturi.comnano ~/.ssh/known_hosts
This will open the known_hosts file in the Nano text editor. You can then use the arrow keys to navigate to the entry that you want to remove and delete it using the delete or backspace key.
Once you have removed the entry, save the file by pressing Control-X and then pressing Y when prompted to save the changes. The entry for the known host will now be removed from the known_hosts file, and you will no longer be able to connect to the server using SSH.
Note that you may need to enter your Mac's password when editing the known_hosts file, as the file is protected by the operating system to prevent unauthorized access.