usage()
already_fixed = atoi(os.environ.get('BUP_FORCE_TTY'))
-if subcmd_name in ['ftp', 'help']:
+if subcmd_name in ['mux', 'ftp', 'help']:
already_fixed = True
fix_stdout = not already_fixed and os.isatty(1)
fix_stderr = not already_fixed and os.isatty(2)