Invisible files

Tom C

Files beginning with a period are invisible from the GUI, just as they are in Unix...

However, some files that do NOT begin with a period also are invisible in the GUI. I'm assuming that Apple has some invisibility parameter carried over from OS 9. How do you set/unset this parameter from the CLI? Did Apple map the OS 9 invisibility property on to an obscure BSD flag like they mapped the locked file property on to uchg?
I believe editing the .hidden file (at the root level of your drive) will change which non-dot files are invisible. I may be wrong though.