The table below enumerates the vendor and the name of their on-line manual utility.
Most Linux distributions do not include such a tool. But the /usr/share/doc directory contains documentation on many of the packages, many of which is in HTML so can be read with any Web Browser.
The Linux Documentation Project, located on the web at
http://www.linux.org/docs/offers generic linux documentation on-line.
The Research Computing Support Group also has linux documentation on their web site at
(access to that site may be limited to internal NRC only).