diff --git a/scripts/common/puphpet.sh b/scripts/common/puphpet.sh
index ed2b694b9..8dc858f75 100644
--- a/scripts/common/puphpet.sh
+++ b/scripts/common/puphpet.sh
@@ -25,7 +25,7 @@ fi
 /bin/bash /.puphpet-stuff/shell/initial-setup.sh /.puphpet-stuff || true
 /bin/bash /.puphpet-stuff/shell/install-puppet.sh || true
 
-if "${OS}" == 'centos'; then
+if [ "${OS}" == 'centos' ]; then
     yum clean metadata
     yum -y update