diff --git a/xCAT-server/lib/xcat/plugins/dhcp.pm b/xCAT-server/lib/xcat/plugins/dhcp.pm
index fc40e2e57..10bedbae8 100755
--- a/xCAT-server/lib/xcat/plugins/dhcp.pm
+++ b/xCAT-server/lib/xcat/plugins/dhcp.pm
@@ -1513,7 +1513,7 @@ sub process_request
                     if (/!remote!/) { next; }
                     $ifarg .= " $_";
                 }
-                $ifarg = s/\=\" /\=\"/;
+                $ifarg =~ s/\=\" /\=\"/;
                 $ifarg .= "\"\n";
 
                 while (<DHCPD_FD>) {