docker/cli · error

bad mode specified: %s

Error message

bad mode specified: %s

What it means

Error "bad mode specified: %s" thrown in docker/cli.

Source

Thrown at cli/command/container/opts.go:1122

	}
	switch len(split) {
	case 1:
		containerPath = split[0]
		val = path.Clean(containerPath)
	case 2:
		if isValid := validator(split[1]); isValid {
			containerPath = split[0]
			mode = split[1]
			val = fmt.Sprintf("%s:%s", path.Clean(containerPath), mode)
		} else {
			containerPath = split[1]
			val = fmt.Sprintf("%s:%s", split[0], path.Clean(containerPath))
		}
	case 3:
		containerPath = split[1]
		mode = split[2]
		if isValid := validator(split[2]); !isValid {
			return val, fmt.Errorf("bad mode specified: %s", mode)
		}
		val = fmt.Sprintf("%s:%s:%s", split[0], containerPath, mode)
	}

	if !path.IsAbs(containerPath) {
		return val, fmt.Errorf("%s is not an absolute path", containerPath)
	}
	return val, nil
}

// validateAttach validates that the specified string is a valid attach option.
func validateAttach(val string) (string, error) {
	s := strings.ToLower(val)
	if slices.Contains([]string{"stdin", "stdout", "stderr"}, s) {
		return s, nil
	}
	return val, errors.New("valid streams are STDIN, STDOUT and STDERR")
}

View on GitHub (pinned to e9452d6e78)

When it happens

Trigger: Thrown at cli/command/container/opts.go:1122 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of docker/cli@e9452d6e78 (2026-08-01). Data as JSON: /data/errors/f8faeda49fa53b28.json. Report an issue: GitHub.