diff --git a/roles/taskotron/buildmaster-configure/templates/taskotron.master.cfg.j2 b/roles/taskotron/buildmaster-configure/templates/taskotron.master.cfg.j2
index 293cc115f5..515427de74 100644
--- a/roles/taskotron/buildmaster-configure/templates/taskotron.master.cfg.j2
+++ b/roles/taskotron/buildmaster-configure/templates/taskotron.master.cfg.j2
@@ -154,7 +154,7 @@ from buildbot.steps.master import MasterShellCommand
 factory = BuildFactory()
 
 # clean out /var/tmp/taskotron (see T253)
-factory.addStep(ShellCommand(command=["rm", "-rf", "/var/tmp/taskotron/*"], name="rm_tmp", descriptionDone=['Clean tmp']))
+factory.addStep(ShellCommand(command="rm -rf /var/tmp/taskotron/*", name="rm_tmp", descriptionDone=['Clean tmp']))
 
 # clean the log (see T230)
 factory.addStep(ShellCommand(command=["rm", "-f", "/var/log/taskotron/taskotron.log"], name="rm_log", descriptionDone=['Clean log']))