Kate

Kate has syntax highlighting for languages ranging from C and C++ to HTML to bash scripts and the ability to create and maintain projects. You can open several files at once in Kate. Kate is part of the KDE environment but also works under XUbuntu. It can only be run in graphical mode.

To start kate in graphical mode, open a terminal window and type

kate filename &

or select Applications -> Accessories -> Kate from the XUbuntu menus.

Kate comes with well documented help. Open kate and select Help (from the top right hand side) -> Kate Handbook.

You can use google to search for kate tutorials.

There is more information at http://kate-editor.org/