muesli/duf · error

unknown style option: %s

Error message

unknown style option: %s

What it means

parseStyle maps the --style CLI option to a tablewriter style. Only "unicode" (table.StyleRounded) and "ascii" (table.StyleDefault) are accepted; any other value returns "unknown style option: %s". It is a strict enum validation of a user-supplied flag.

Source

Thrown at main.go:99

		if err != nil {
			return nil, err
		}

		i = append(i, col)
	}

	return i, nil
}

// parseStyle converts user-provided style option into a table.Style.
func parseStyle(styleOpt string) (table.Style, error) {
	switch styleOpt {
	case "unicode":
		return table.StyleRounded, nil
	case "ascii":
		return table.StyleDefault, nil
	default:
		return table.Style{}, fmt.Errorf("unknown style option: %s", styleOpt)
	}
}

// parseCommaSeparatedValues parses comma separated string into a map.
func parseCommaSeparatedValues(values string) map[string]struct{} {
	m := make(map[string]struct{})
	for _, v := range strings.Split(values, ",") {
		v = strings.TrimSpace(v)
		if len(v) == 0 {
			continue
		}

		v = strings.ToLower(v)
		m[v] = struct{}{}
	}
	return m
}

View on GitHub (pinned to 4636deb4a7)

Solutions

1. Run with --style unicode or --style ascii exactly as lowercase.
2. Check the tool's help output for the accepted style values.
3. If you control the code, normalize input with strings.ToLower before the switch and/or add the desired style as a new case.

Example fix

// before
switch styleOpt {
case "unicode": return table.StyleRounded, nil
case "ascii": return table.StyleDefault, nil
}
// after
switch strings.ToLower(styleOpt) {
case "unicode", "rounded": return table.StyleRounded, nil
case "ascii", "default": return table.StyleDefault, nil
}

validStyles := map[string]bool{"unicode": true, "ascii": true}
if !validStyles[style] {
	return fmt.Errorf("style must be unicode or ascii, got %q", style)
}

style, err := parseStyle(styleOpt)
if err != nil {
	fmt.Fprintln(os.Stderr, err)
	os.Exit(1)
}

When it happens

Trigger: Calling the binary with --style set to anything other than "unicode" or "ascii", e.g. --style rounded, --style fancy, --style UNICODE (case-sensitive).

Common situations: Users guess at style names, copy a style name from another table library, or capitalize the value expecting case-insensitive handling.

Understand the failure class

Background: Invalid enum value errors: "Unknown type", "Invalid scope", "must be one of" — when a string is not on the library's allowed list — this error's family across 23 libraries.

Related errors

• unknown device group: %s
• error parsing avail-threshold: invalid option '%s'
• error parsing usage-threshold: invalid option '%s'
• unknown column: %s (valid: %s)
• '%s' is not valid, must have integer with optional SI prefix

AI-assisted analysis of muesli/duf@4636deb4a7 (2026-09-06). Data as JSON: /api/errors/2366fbb605d0cc11. Report an issue: GitHub.