-# Update the link to the current version of the DTD
-ln -sf /etc/sgml/sgml-docbook-3.0.cat /etc/sgml/sgml-docbook.cat
-
-%postun
-# Update the centralized catalog corresponding to this version of the DTD
-/usr/bin/install-catalog --remove /etc/sgml/sgml-docbook-3.0.cat /usr/share/sgml/sgml-iso-entities-8879.1986/catalog > /dev/null
-/usr/bin/install-catalog --remove /etc/sgml/sgml-docbook-3.0.cat /usr/share/sgml/docbook/sgml-dtd-3.0/catalog > /dev/null
-
-# The following lines are for the case in which the style sheets were
-# not uninstalled because there is still another DTD
-STYLESHEETS=$(echo /usr/share/sgml/docbook/dsssl-stylesheets-*)
-STYLESHEETS=${STYLESHEETS##*/dsssl-stylesheets-}
-if [ "$STYLESHEETS" != "*" ]; then
- /usr/bin/install-catalog --remove /etc/sgml/sgml-docbook-3.0.cat /usr/share/OpenJade/catalog > /dev/null
- /usr/bin/install-catalog --remove /etc/sgml/sgml-docbook-3.0.cat /usr/share/sgml/docbook/dsssl-stylesheets-$STYLESHEETS/catalog > /dev/null
+%post
+if ! grep -q /etc/sgml/sgml-docbook-3.0.cat /etc/sgml/catalog ; then
+ /usr/bin/install-catalog --add /etc/sgml/sgml-docbook-3.0.cat /usr/share/sgml/docbook/sgml-dtd-3.0/catalog > /dev/null