3.2.1 Environment

The system is currently implemented to run under the X Window System, Version 11, and you must be using a console or monitor running X11 or a compatible windowing system.

FDR insists on one variable being set in its environment: FDRHOME must be set to the (fully qualified) name of the directory containing the FDR `LICENCE' file, typically the root directory of the FDR installation. If this variable is not set, the tool will terminate immediately with an error.

Other environment variables may be set, to select preferred editors and web browsers.

• The environment variable FDREDIT may contain the name of the editor you prefer to invoke to view script files. If this is not set, then the environment variables VISUAL and EDITOR are examined (in that order) and if none of these is set the editor vi is selected. In all of the above cases, an X terminal application is launched to host the editor (so the program xterm needs to be found along your search path); if your chosen editor opens its own X-window (like xedit and modern versions of Emacs), then supply its name in the environment variable FDRXEDIT instead, which overrides the other variables and launches the editor without the extra terminal application.

• The FDRBROWSER environment variable, if set, determines which browser to use to view the hypertext version of the manual. The browser is assumed to be an X11 application and will be launched directly, rather than inside an xterm. If FDRBROWSER is not set, a simple browser written in Tcl/Tk will be used.

Other environment variables allow you to control the location of various components of FDR, and to control its paging strategies. These are documented in D. Configuration.