wtfutil/wtf · error

failed to parse command output '%s' as float64: %w

Error message

failed to parse command output '%s' as float64: %w

What it means

Raised in execValueCmd when strconv.ParseFloat fails on the trimmed stdout of a configured value command (minimum/maximum/current): the command ran successfully but its output is not a plain numeric value (e.g. text, units, or multiple lines), so it cannot be converted to float64.

Source

Thrown at modules/progress/widget.go:155

		return title, widget.content(), false
	})
}

func (widget *Widget) execValueCmd(cmd string) (float64, error) {
	if widget.shell == "" {
		return -1, errShellUndefined
	}

	out, err := exec.Command(widget.shell, "-c", cmd).Output()
	if err != nil {
		return -1, err
	}

	outStr := strings.TrimSpace(string(out))

	val, err := strconv.ParseFloat(outStr, 64)
	if err != nil {
		return -1, fmt.Errorf("failed to parse command output '%s' as float64: %w", outStr, err)
	}

	return val, nil
}

func (widget *Widget) buildProgressBar(percent string) *progress.Model {
	pOpts := []progress.Option{
		progress.WithWidth(widget.calcBarWidth(percent)),
		progress.WithoutPercentage(),
	}

	if widget.settings.solid != "" {
		pOpts = append(pOpts, progress.WithSolidFill(widget.settings.solid))
	} else {
		pOpts = append(pOpts, progress.WithGradient(
			widget.settings.gradientA,
			widget.settings.gradientB,
		))

View on GitHub (pinned to bb838c1ccb)

Solutions

1. Adjust the command so it outputs only a bare number (strip units/labels, e.g. via awk or cut)
2. Check the command's output for warnings or logs mixed into stdout
3. Trim extra whitespace/characters the command emits
4. Test the exact command with $SHELL -c '<cmd>' to confirm the output parses as a float

When it happens

Trigger: Thrown at modules/progress/widget.go:155 when the library encounters an invalid state.

Common situations: See trigger scenarios.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

AI-assisted analysis of wtfutil/wtf@bb838c1ccb (2026-09-03). Data as JSON: /api/errors/a9625c56a71f43a7. Report an issue: GitHub.