diff --git a/doc/preproc.sh b/doc/preproc.sh
index 715764d..a7e732e 100755
--- a/doc/preproc.sh
+++ b/doc/preproc.sh
@@ -8,6 +8,7 @@
 # - Replaces all the occurrences of {{INSTALL_PREFIX}} by the value of
 #   the INSTALL_PREFIX environment variable.
 
-sed "{ \
-  s/{{OWLPS_VERSION}}/${OWLPS_VERSION}/g ; \
-  s@{{INSTALL_PREFIX}}@${INSTALL_PREFIX}@g }" $@
+sed "{
+  s@{{OWLPS_VERSION}}@${OWLPS_VERSION}@g
+  s@{{INSTALL_PREFIX}}@${INSTALL_PREFIX}@g
+  }" $@