diff --git a/debian/libghc6-cabal-dev.postinst b/debian/libghc6-cabal-dev.postinst
index 513727d861043eebb91ab0dfcf6a7cedb0fb4430..fa5fc562dc04a408a03f1aa2fe9f40e97ce9cda9 100644
--- a/debian/libghc6-cabal-dev.postinst
+++ b/debian/libghc6-cabal-dev.postinst
@@ -19,7 +19,7 @@ set -e
 
 case "$1" in
     configure)
-        /usr/share/doc/libghc6-cabal-dev/register.sh
+        source /usr/share/doc/libghc6-cabal-dev/register.sh
     ;;
 
     abort-upgrade|abort-remove|abort-deconfigure)
diff --git a/debian/libghc6-cabal-dev.prerm b/debian/libghc6-cabal-dev.prerm
index e60c4bf10c0df45d4ee7545fcf1b3e7df54f9227..92d19be4d4f9362890da91a900214744a179db93 100644
--- a/debian/libghc6-cabal-dev.prerm
+++ b/debian/libghc6-cabal-dev.prerm
@@ -19,7 +19,7 @@ set -e
 
 case "$1" in
     remove|upgrade|deconfigure)
-        /usr/share/doc/libghc6-cabal-dev/unregister.sh
+        source /usr/share/doc/libghc6-cabal-dev/unregister.sh
         rm -f /usr/lib/haskell-packages/ghc6/lib/Cabal-0.5/HSCabal*.o
 
 #       install-info --quiet --remove /usr/info/missingh.info.gz