diff --git a/make/rules.mk b/make/rules.mk
index f2dcd57c..651254fb 100644
--- a/make/rules.mk
+++ b/make/rules.mk
@@ -97,10 +97,10 @@ love:
 	@echo "Not war?"
 
 cvsupdate update:
-	if [ -d "CVS" ]; then cvs update -dP; else git pull; fi
+	if [ -d "CVS" ]; then cvs update -dP || exit 1; else git pull || exit 1; fi
 
 cvsdiff diff:
-	if [ -d "CVS" ]; then cvs diff -dP; else git --no-pager diff; fi
+	if [ -d "CVS" ]; then cvs diff -dP || exit 1; else git --no-pager diff || exit 1; fi
 
 prepend_header:
 	set -e; for f in $(SRC_UNHEADERED); do sh $(TOPDIR)/hdr/prepend_header.sh $$f; done