private static void knownHosts(SecureShell sch)
 {
     DirectoryInfo home = FS.userHome();
     if (home == null)
         return;
     var known_hosts = new FileInfo(Path.Combine(home.ToString(), ".ssh/known_hosts"));
     try
     {
         using (var s = new StreamReader(known_hosts.FullName))
         {
             sch.SetKnownHosts(s);
         }
     }
     catch (FileNotFoundException)
     {
         // Oh well. They don't have a known hosts in home.
     }
     catch (IOException)
     {
         // Oh well. They don't have a known hosts in home.
     }
 }