diff --git a/.gitlab-ci/lib.sh b/.gitlab-ci/lib.sh
index c804eee..4eb7000 100755
--- a/.gitlab-ci/lib.sh
+++ b/.gitlab-ci/lib.sh
@@ -15,14 +15,14 @@ find_base() {
 	local base=$(git merge-base $r1 $r2)

 	if [[ -z $base ]] ; then
-		echo "No common ancestor between $r1 and $r2."
-		echo "Make sure your master branch is up-to-date."
+		echo "No common ancestor between $r1 and $r2." >&2
+		echo "Make sure your master branch is up-to-date." >&2
 		exit 1
 	fi

 	if [[ $(git log --oneline $base..$r2 | wc -l) -gt 50 ]] ; then
-		echo "Common ancestor $base of $r1 and $r2 is too far in history."
-		echo "Make sure your master branch is up-to-date."
+		echo "Common ancestor $base of $r1 and $r2 is too far in history." >&2
+		echo "Make sure your master branch is up-to-date." >&2
 		exit 1
 	fi