fshell is the Symbian equivalent of bash + telnet + a posix-like set of command-line tools. In other words it's a console framework for Symbian OS with support for remote connections and a suite of tools for debugging the device.
GDesk is a customizable and extendable desktop system for Symbian (UIQ 3, S60 3rd and 5th editions). Icons can be placed on the desktop representing applications, page links and plug-ins; these can then be launched by tapping them.