The official extension known to a linux system (make) are:   
      
   .out .a .ln .o .c .cc .C .cpp .p .f .F .m .r .y .l .ym .yl .s .S .mod   
   .sym .def .h .info .dvi .tex .texinfo .texi .txinfo .w .ch .web .sh   
   .elc .el .out .a .ln .o .c .cc .C .cpp .p .f .F .m .r .y .l .ym .yl .s   
   .S .mod .sym .def .h .info .dvi .tex .texinfo .texi .txinfo .w .ch   
   .web .sh .elc .el   
      
   There is no extension for Forth files. Moreover .f .F have been taken   
   for FORTRAN.   
   Note that there is no extension for Python. Apparently if you have given   
   up compiling to executables, you don't register with make. All the same   
   there is a de facto extension for Python that is py and half-compiled .pyc.   
      
   For Forth we've seen: .f .F .frt .FRT .fth .4th .fs   
   Are there more?   
      
   I'd like to see an official extension. This would help with uniformization   
   of the Forth language and finding forth sources on the web.   
   For example build in rules to go from a source   
   to an executable, or syntax coloring in editors.   
      
   The gforth authors have the most influence in GNU linux. Unfortunately   
   they seem to use the .f suffix exclusively. Would they push for an   
   official extension?   
   gforth also uses .fs for non forth files, scripts, while others use it   
   for plain Forth files.   
      
   Groetjes Albert   
   --   
   Don't praise the day before the evening. One swallow doesn't make spring.   
   You must not say "hey" before you have crossed the bridge. Don't sell the   
   hide of the bear until you shot it. Better one bird in the hand than ten in   
   the air. First gain is a cat purring.            - the Wise from Antrim -   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)