diff --git a/scripts/sphinx-pre-install b/scripts/sphinx-pre-install
index f230e65329a2..101ddd00bf02 100755
--- a/scripts/sphinx-pre-install
+++ b/scripts/sphinx-pre-install
@@ -371,7 +371,7 @@ sub give_redhat_hints()
 	#
 	# Checks valid for RHEL/CentOS version 7.x.
 	#
-	if (! $system_release =~ /Fedora/) {
+	if (!($system_release =~ /Fedora/)) {
 		$map{"virtualenv"} = "python-virtualenv";
 	}