diff --git a/install.sh b/install.sh
index 957c553..10d56d4 100755
--- a/install.sh
+++ b/install.sh
@@ -64,6 +64,8 @@ function install_if()
     local dst="$2"
     shift 2
 
+    true < "$src" || exit 1
+
     if need_update "$src" "$dst"; then
         dir="$(dirname "$dst")"
         test -d "$dir" || mkdir -p "$dir"