go-delve/delve · error

unknown argument %q to 'target follow-exec'

Error message

unknown argument %q to 'target follow-exec'

What it means

`target follow-exec` accepts at most one flag: `-on` (implicit/default), `-off`, or `-regex <pattern>`. Any other token is rejected with this message by the default case.

Source

Thrown at pkg/terminal/command.go:3576

				fmt.Fprintf(t.stdout, "Follow exec is disabled.\n")
			}
			return nil
		}
		argv = config.Split2PartsBySpace(argv[1])
		switch argv[0] {
		case "-on":
			var regex string
			if len(argv) == 2 {
				regex = argv[1]
			}
			t.client.FollowExec(true, regex)
		case "-off":
			if len(argv) > 1 {
				return errors.New("too many arguments")
			}
			t.client.FollowExec(false, "")
		default:
			return fmt.Errorf("unknown argument %q to 'target follow-exec'", argv[0])
		}
		return nil
	case "switch":
		tgts, err := t.client.ListTargets()
		if err != nil {
			return err
		}
		pid, err := strconv.Atoi(argv[1])
		if err != nil {
			return err
		}
		found := false
		for _, tgt := range tgts {
			if tgt.Pid == pid {
				found = true
				t.client.SwitchThread(tgt.CurrentThread.ID)
			}
		}

View on GitHub (pinned to a23773e6c3)

Solutions

1. Use `target follow-exec -regex <pattern>` to filter exec'd children by pattern
2. Use `target follow-exec -off` to disable
3. Use `target follow-exec -on` (or bare) to enable for all children
4. Check flag spelling and case

Example fix

// before
target follow-exec server*
// after
target follow-exec -regex server*

if !validFollowExecArg(argv[0]) {
    return fmt.Errorf("%q invalid; use -on, -off, or -regex <pattern>", argv[0])
}

When it happens

Trigger: Running e.g. `target follow-exec -all`, `target follow-exec foo`, or any misspelled flag.

Common situations: Typos (`-of` instead of `-off`); trying to pass an exec pattern directly without the `-regex` flag; muscle memory from other debuggers.

Related errors

• command not available
• you must specify a thread
• too many arguments to goroutine
• not enough arguments
• Invalid frame %d

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/4c16ca4a06b4271b. Report an issue: GitHub.