--- setuptex.orig	2011-09-22 22:36:37.000000000 +0900
+++ setuptex	2011-09-22 22:38:12.000000000 +0900
@@ -148,13 +148,16 @@
 	fi
 
 # ConTeXt binaries have to be added to PATH
-TEXMFOS=$TEXROOT/texmf-$platform
-PATH=$TEXMFOS/bin:$PATH
+export TEXMFOS=$TEXROOT/texmf-$platform
+export PATH=$TEXMFOS/bin:$PATH
 # TODO: we could set OSFONTDIR on Mac for example
 
 # not sure why this would be needed
 # export CTXMINIMAL=yes
 
+# unset variables that won't be used lately
+unset platform cpu system OWNPATH SCRIPTPATH ARGPATH
+
 else
 	echo "provide a proper tex root (like '. setuptex /something/tex')" ;
 fi