diff --git a/pkg_postgresql.postinstall b/pkg_postgresql.postinstall
index 255a760..af0d32e 100644
--- a/pkg_postgresql.postinstall
+++ b/pkg_postgresql.postinstall
@@ -16,7 +16,7 @@ chown postgres:postgres /opt/postgresql
 chown postgres:postgres /var/opt/postgresql/data/
 
 su -c postgres "/opt/postgresql/bin/initdb -D /var/opt/postgresql/data"
-sed -i "s,#default_with_oids\ =\ off,default_with_oids\ =\ on," /var/opt/postgresql/data/postgresql.conf
-sed -i "s,#backslash_quote\ =\ off,backslash_quote\ =\ on," /var/opt/postgresql/data/postgresql.conf
-sed -i "s,#add_missing_from\ =\ off,add_missing_from\ =\ on," /var/opt/postgresql/data/postgresql.conf
+sed -i -e "s,^#default_with_oids\ =\ off,default_with_oids\ =\ on," \
+    -e "s,^#backslash_quote\ =\ safe_encoding,backslash_quote\ =\ on," \
+    -e "s,^#add_missing_from\ =\ off,add_missing_from\ =\ on," /var/opt/postgresql/data/postgresql.conf