diff --git a/xmlrpc/emulabserver.py.in b/xmlrpc/emulabserver.py.in
index 5b2cd7a6901965679da78cc1cb5cb566fe20486f..b82263e401eed992f9a302e333e1ff1459e340c5 100755
--- a/xmlrpc/emulabserver.py.in
+++ b/xmlrpc/emulabserver.py.in
@@ -3263,7 +3263,7 @@ class node:
 
         argstr = escapeshellarg(argdict["op"])
         argstr += " " + filename
-        argstr += " " + escapeshellarg(" ".join(argdict["nodes"]))
+        argstr += " " + " ".join(map(escapeshellarg,argdict["nodes"]))
 
         (exitval, output) = runcommand(TBDIR + "/bin/tbuisp " + argstr)
         if exitval: