diff --git a/munet/base.py b/munet/base.py
index 06ca4de..15e8158 100644
--- a/munet/base.py
+++ b/munet/base.py
@@ -1206,7 +1206,7 @@ def run_in_window(
         # XXX need to test ssh in Xterm
         sudo_path = get_exec_path_host(["sudo"])
         # This first test case seems same as last but using list instead of string?
-        if self.is_vm and self.use_ssh:  # pylint: disable=E1101
+        if self.is_vm and self.use_ssh and not ns_only:  # pylint: disable=E1101
             if isinstance(cmd, str):
                 cmd = shlex.split(cmd)
             cmd = ["/usr/bin/env", f"MUNET_NODENAME={self.name}"] + cmd
diff --git a/munet/cli.py b/munet/cli.py
index f631073..133644e 100644
--- a/munet/cli.py
+++ b/munet/cli.py
@@ -325,13 +325,14 @@ def get_shcmd(unet, host, kinds, execfmt, ucmd):
     if not execfmt:
         return ""
 
-    # Do substitutions for {} in string
+    # Do substitutions for {} and {N} in string
     numfmt = len(re.findall(r"{\d*}", execfmt))
     if numfmt > 1:
         ucmd = execfmt.format(*shlex.split(ucmd))
     elif numfmt:
         ucmd = execfmt.format(ucmd)
-    elif len(re.findall(r"{[a-zA-Z_][0-9a-zA-Z_\.]*}", execfmt)):
+    # look for any pair of {}s but do not count escaped {{ or }}
+    elif len(re.findall(r"{[^}]+}", execfmt.replace("{{", "").replace("}}", ""))):
         if execfmt.endswith('"'):
             fstring = "f'''" + execfmt + "'''"
         else:
diff --git a/munet/native.py b/munet/native.py
index fecf709..03408c4 100644
--- a/munet/native.py
+++ b/munet/native.py
@@ -455,13 +455,14 @@ def pytest_hook_open_shell(self):
 
             bps = self.unet.cfgopt.getoption("--gdb-breakpoints", "").split(",")
             for bp in bps:
-                gdbcmd += f" '-ex=b {bp}'"
+                if bp:
+                    gdbcmd += f" '-ex=b {bp}'"
 
             cmds = self.config.get("gdb-run-cmd", [])
             for cmd in cmds:
                 gdbcmd += f" '-ex={cmd}'"
 
-            self.run_in_window(gdbcmd)
+            self.run_in_window(gdbcmd, ns_only=True)
         elif should_gdb and use_emacs:
             gdbcmd = gdbcmd.replace("gdb ", "gdb -i=mi ")
             ecbin = self.get_exec_path("emacsclient")