Right, everything is a filesystem in Plan 9. It's really elegant. Many people think Unix is elegant, which it is, but then they realize there is a higher plane of elegance in interface design when they encounter Plan 9.
In case anyone is wondering how the Plan 9 approach could accommodate special devices and so forth (i.e. objects that do not conform exactly to the same interface), there is an escape hatch called a control file, and you can do the equivalent of an ioctl by writing device-specific commands to the control file. But by and large, P9 represents everything as a filesystem and thus makes it really easy to reconnect the piping any which way the user likes.
In case anyone is wondering how the Plan 9 approach could accommodate special devices and so forth (i.e. objects that do not conform exactly to the same interface), there is an escape hatch called a control file, and you can do the equivalent of an ioctl by writing device-specific commands to the control file. But by and large, P9 represents everything as a filesystem and thus makes it really easy to reconnect the piping any which way the user likes.
Every hacker needs to see Plan 9 in action.