diff --git a/xCAT-test/autotest/testcase/installation/ubuntu_diskless_installation_vm b/xCAT-test/autotest/testcase/installation/ubuntu_diskless_installation_vm
index c642ca7b3..ec46859fe 100644
--- a/xCAT-test/autotest/testcase/installation/ubuntu_diskless_installation_vm
+++ b/xCAT-test/autotest/testcase/installation/ubuntu_diskless_installation_vm
@@ -3,7 +3,7 @@ os:Linux
 
 cmd:copycds $$ISO
 check:rc==0
-cmd:if [[ "__GETNODEATTR($$CN,arch)__" =~ "x86_64" ]];then chdef -t node -o $$CN vmstorage=dir:///var/lib/libvirt/images/ && rmvm $$CN -f  &&  mkvm $$CN ; fi
+cmd:if [ "__GETNODEATTR($$CN,arch)__" = "x86_64" ]; then chdef -t node -o $$CN vmstorage=dir:///var/lib/libvirt/images/ && rmvm $$CN -f  &&  mkvm $$CN ; fi
 cmd:makedns -n
 check:rc==0
 cmd:makedhcp -n