Well, thank you for this information about some basic knowledge about linux and ssh, @MorrisC, but how is this related to Plesk 12 or what sort of issues depend on it, or do you experience?
if you do initial installation using plesk iso with network issues. The installation will not start and post a message there. After fixing the network issues and complete installation, plesk left a message at that file with some installation got interrupted every time you sign in via ssh to all users . Just need to remove that message from that file and the message will not appear after signing in.