diff --git a/Doit b/Doit
index 5557c82f16..ab5b4be3c3 100755
--- a/Doit
+++ b/Doit
@@ -34,7 +34,7 @@ do
 			version=$(expr "$installed" : '.*\.g\([0-9a-f]*\)$') ||
 			version=v$(expr "$installed" : 'git version \(.*\)')
 		} &&
-		version=$(git rev-parse --verify "$version^0") &&
+		version=$(git rev-parse --verify "$version^0" 2>/dev/null) &&
 		test "z$version" = "z$revision"
 	then
 		echo "* up-to-date version \"$installed\" is already installed from $branch"
diff --git a/V b/V
index a0c4b6d73d..5386aee106 100755
--- a/V
+++ b/V
@@ -6,7 +6,7 @@ do
 	version=$(expr "$installed" : '.*\.g\([0-9a-f]*\)$') ||
 	version=v$(expr "$installed" : 'git version \(.*\)')
 
-	version=$(git rev-parse --verify "$version^0")
+	version=$(git rev-parse --verify "$version^0" 2>/dev/null)
 	revision=$(git show-ref -s --verify "refs/heads/$v")
 	if test "z$version" = "z$revision"
 	then