kovidgoyal/kitty · error

invalid previewer specification: %#v with error: no command

Error message

invalid previewer specification: %#v with error: no command specified

What it means

The previewer spec tokenized into fewer than 2 shell words, meaning only a pattern was given with no command to run. Every previewer needs 'prefix:pattern command args...'.

Source

Thrown at kittens/choose_files/main.go:300

	use_mimetype bool
}

func (p previewer) matches(fname, mt string) bool {
	q := utils.IfElse(p.use_mimetype, mt, fname)
	matched, err := filepath.Match(p.pattern, q)
	return matched && err == nil
}

var previewers []previewer

func load_previewers(cfg *Config) (err error) {
	for _, spec := range cfg.Previewer {
		parts, err := shlex.Split(spec)
		if err != nil {
			return fmt.Errorf("invalid previewer specification: %#v with error: %w", spec, err)
		}
		if len(parts) < 2 {
			return fmt.Errorf("invalid previewer specification: %#v with error: no command specified", spec)
		}
		prefix, pattern, found := strings.Cut(parts[0], ":")
		if !found {
			return fmt.Errorf("invalid previewer specification: %#v with error: no prefix in pattern specification", spec)
		}
		previewers = append(previewers, previewer{parts[1:], pattern, prefix == "mime"})
	}
	return
}

func load_config(opts *Options) (ans *Config, err error) {
	ans = NewConfig()
	p := config.ConfigParser{LineHandler: ans.Parse}
	err = p.LoadConfig("choose-files.conf", opts.Config, opts.Override)
	if err != nil {
		return nil, err
	}
	ans.KeyboardShortcuts = config.ResolveShortcuts(ans.KeyboardShortcuts)

View on GitHub (pinned to 6d5d0c4406)

Solutions

1. Add the command after the pattern: --previewer 'mime:image/* chafa {file}'
2. Re-check the previewer syntax in kitty's choose-files documentation

Example fix

# before
--previewer 'mime:image/*'
# after
--previewer 'mime:image/* chafa --format symbols {file}'

parts, _ := shlex.Split(spec); if len(parts) < 2 { /* reject: no command given */ }

When it happens

Trigger: Passing a spec like '--previewer name:*.png' with no command after the pattern.

Common situations: Misreading kitty docs and omitting the command; copy-paste truncation losing the command part.

Related errors

• invalid previewer specification: %#v with error: no prefix i
• invalid previewer specification: %#v with error: %w
• invalid value %s in video_preview
• This should be run as kitten broadcast
• No option named: {k}

AI-assisted analysis of kovidgoyal/kitty@6d5d0c4406 (2026-08-27). Data as JSON: /api/errors/ee4b0591e5b8b506. Report an issue: GitHub.