pranshuparmar/witr · error

must specify --pid, --port, --file, --container, or a proces

Error message

must specify --pid, --port, --file, --container, or a process name

What it means

runApp validates that at least one inspection target was supplied on the command line. collectTargetsInOrder found no --pid, --port, --file, --container flag or bare process-name argument, so there is nothing to inspect. The CLI returns ExitInvalidInput for this user error.

Source

Thrown at internal/app/app.go:203

		return runInteractive()
	}

	flags := appFlags{
		env:     envFlag,
		exact:   boolFlag(cmd, "exact"),
		short:   boolFlag(cmd, "short"),
		tree:    boolFlag(cmd, "tree"),
		json:    boolFlag(cmd, "json"),
		warn:    boolFlag(cmd, "warnings"),
		noColor: boolFlag(cmd, "no-color"),
		verbose: boolFlag(cmd, "verbose"),
	}

	// Collect all targets preserving command-line order
	targets := collectTargetsInOrder(os.Args[1:], args, flagTakesValue(cmd))

	if len(targets) == 0 {
		return withExitCode(ExitInvalidInput, fmt.Errorf("must specify --pid, --port, --file, --container, or a process name"))
	}

	outw := cmd.OutOrStdout()
	outp := output.NewPrinter(outw)
	multiMode := len(targets) > 1
	colorEnabled := useColor(flags, outw)

	// For JSON multi-output, collect all JSON strings and wrap in array
	var jsonResults []string
	highestExit := ExitOK

	for i, t := range targets {
		if multiMode && !flags.json {
			printDivider(outp, t, colorEnabled, i > 0)
		}

		exitCode := processTarget(cmd, outw, outp, t, flags, multiMode, &jsonResults)
		if exitCode > highestExit {

View on GitHub (pinned to dc4fa1da82)

Solutions

1. Add a target: pass --pid <pid>, --port <port>, --file <path>, --container <name>, or a bare process name.
2. Run with --help to see the exact accepted target flags.
3. Check your shell script for an empty/misspelled target variable (e.g. "$PID" unset).
4. If scripting, guard against an empty target before invoking the tool.

Example fix

// before
$ errlookup
// after
$ errlookup --pid 1234
$ errlookup --port 8080
$ errlookup myserver

args := os.Args[1:]
targeted := false
for _, a := range args {
    if strings.HasPrefix(a, "--pid") || strings.HasPrefix(a, "--port") ||
        strings.HasPrefix(a, "--file") || strings.HasPrefix(a, "--container") ||
        !strings.HasPrefix(a, "-") {
        targeted = true
        break
    }
}
if !targeted {
    return errors.New("no target given: pass --pid, --port, --file, --container, or a process name")
}

if err := runApp(cmd, args); err != nil {
    var ec *ExitCodeError
    if errors.As(err, &ec) && ec.Code == ExitInvalidInput {
        cmd.Usage()
    }
    return err
}

When it happens

Trigger: Running the binary with no arguments at all, or with only option flags that take no target (e.g. only --json or --exact), or flags whose values were consumed without matching a target keyword.

Common situations: Typing the tool name alone to 'see usage'; shell scripts that build the command dynamically and end up with an empty target variable; misremembering flag names (e.g. --pids) so no target is recognized.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• completed with exit code %d
• no matching process found
• no container found matching %q

AI-assisted analysis of pranshuparmar/witr@dc4fa1da82 (2026-09-01). Data as JSON: /api/errors/f79b218742a01613. Report an issue: GitHub.