Attached is a first crack at patching lyx-1.5 to prefer using xdg-open (1) to open external files/urls from lyx.
Comments? -- Rex (1) from xdg-utils http://portland.freedesktop.org/, in particular, http://portland.freedesktop.org/xdg-utils-1.0/xdg-open.html
--- lyx-1.5.0beta1/lib/configure.py.xdg_open 2007-02-15 14:14:12.000000000 -0600 +++ lyx-1.5.0beta1/lib/configure.py 2007-02-28 11:43:12.000000000 -0600 @@ -238,7 +238,7 @@ checkViewer('a FEN viewer and editor', ['xboard -lpf $$i -mode EditPosition'], rc_entry = [r'\Format fen fen FEN "" "%%" "%%" ""']) # - path, iv = checkViewer('a raster image viewer', ['xv', 'kview', 'gimp']) + path, iv = checkViewer('a raster image viewer', ['xdg-open', 'xv', 'kview', 'gimp']) path, ie = checkViewer('a raster image editor', ['gimp']) addToRC(r'''\Format bmp bmp BMP "" "%s" "%s" "" \Format gif gif GIF "" "%s" "%s" "" @@ -273,23 +273,23 @@ # #checkProg('a Postscript interpreter', ['gs'], # rc_entry = [ r'\ps_command "%%"' ]) - checkViewer('a Postscript previewer', ['gv', 'ghostview -swap', 'kghostview'], + checkViewer('a Postscript previewer', ['xdg-open', 'gv', 'ghostview -swap', 'kghostview'], rc_entry = [r'''\Format eps eps EPS "" "%%" "" "vector" \Format ps ps Postscript t "%%" "" "document,vector"''']) # - checkViewer('a PDF previewer', ['acrobat', 'acroread', 'gv', 'ghostview', \ + checkViewer('a PDF previewer', ['xdg-open', 'acrobat', 'acroread', 'gv', 'ghostview', \ 'xpdf', 'kpdf', 'kghostview'], rc_entry = [r'''\Format pdf pdf "PDF (ps2pdf)" P "%%" "" "document,vector" \Format pdf2 pdf "PDF (pdflatex)" F "%%" "" "document,vector" \Format pdf3 pdf "PDF (dvipdfm)" m "%%" "" "document,vector"''']) # - checkViewer('a DVI previewer', ['xdvi', 'kdvi'], + checkViewer('a DVI previewer', ['xdg-open', 'xdvi', 'kdvi'], rc_entry = [r'\Format dvi dvi DVI D "%%" "" "document,vector"']) if dtl_tools: # Windows only: DraftDVI addToRC(r'\Format dvi2 dvi DraftDVI "" "" "document,vector"') # - checkViewer('an HTML previewer', ['mozilla file://$$p$$i', 'netscape'], + checkViewer('an HTML previewer', ['xdg-open', 'mozilla file://$$p$$i', 'netscape'], rc_entry = [r'\Format html html HTML H "%%" "" "document"']) # checkViewer('Noteedit', ['noteedit'],