golang/go · error

bad -count=: %v

Error message

bad -count=: %v

What it means

Thrown by the match function (backing Grep, Stdout, Stderr commands) in the Go test script framework when the -count=N flag value cannot be parsed as an integer. strconv.Atoi fails on the substring after "-count=". The %v wraps the strconv error.

Source

Thrown at src/cmd/internal/script/cmds.go:655

				"The -q flag suppresses printing of matches.",
			},
			RegexpArgs: firstNonFlag,
		},
		func(s *State, args ...string) (WaitFunc, error) {
			return nil, match(s, args, "", "grep")
		})
}

const matchUsage = "[-count=N] [-q] 'pattern'"

// match implements the Grep, Stdout, and Stderr commands.
func match(s *State, args []string, text, name string) error {
	n := 0
	if len(args) >= 1 && strings.HasPrefix(args[0], "-count=") {
		var err error
		n, err = strconv.Atoi(args[0][len("-count="):])
		if err != nil {
			return fmt.Errorf("bad -count=: %v", err)
		}
		if n < 1 {
			return fmt.Errorf("bad -count=: must be at least 1")
		}
		args = args[1:]
	}
	quiet := false
	if len(args) >= 1 && args[0] == "-q" {
		quiet = true
		args = args[1:]
	}

	isGrep := name == "grep"

	wantArgs := 1
	if isGrep {
		wantArgs = 2
	}

View on GitHub (pinned to b6b368adc5)

Solutions

1. Provide a valid positive integer after -count=, e.g. `-count=3`.
2. Double-check for typos in the flag value.
3. Do not use hex (0x) or float notation — only plain decimal integers are accepted.

Example fix

// Before (broken): stdout -count=three 'pattern'
// After (fixed):  stdout -count=3 'pattern'

// Validate -count flag value before the match command:
func validateCountFlag(arg string) error {
    if !strings.HasPrefix(arg, "-count=") { return nil }
    val := arg[len("-count="):]
    n, err := strconv.Atoi(val)
    if err != nil {
        return fmt.Errorf("-count must be an integer, got %q: %w", val, err)
    }
    if n < 1 {
        return fmt.Errorf("-count must be >= 1, got %d", n)
    }
    return nil
}

When it happens

Trigger: The first argument starts with "-count=" but the remainder is not a valid base-10 integer. E.g. "-count=abc", "-count=", "-count=1.5", or "-count=0x3".

Common situations: Typo in the -count flag value in a test script, or using hex/float notation instead of decimal. Also a stray equals sign or missing number after the flag.

Related errors

• bad -count=: must be at least 1
• found %d matches for %#q in %s
• no match for %#q in %s
• invalid mode: %s
• %s and %s differ

AI-assisted analysis of golang/go@b6b368adc5 (2026-08-12). Data as JSON: /api/errors/f8c2e28256663b2c. Report an issue: GitHub.