我什么时候应该显式调用cmd.Process.Release（）？

I could not know when the command will return the result, and a default timer is set. Then I have this question.

sigChan := make(os.Signal, 1)
signal.Notify(sigChan, SIGCHLD)
cmd := exec.Command(...)
cmd.Start()
select {
    case <-time.After(1e9):
    // kill the process and release?
    case <-sigChan:
    // the process has been terminated
}

Use exec.CommandContext() if you want to terminate the command after a timeout.

Then, you need to wait until the command returns to get its result. So, use cmd.Run() instead of cmd.Start(). If blocking is a concern, then spawn a goroutine that blocks and waits for the command to terminate.

For instance:

go func() {
    ctx, cancel := context.WithTimeout(context.Background(), 100*time.Second)
    defer cancel()
    cmd := exec.CommandContext(ctx, ...)
    err := cmd.Run()
    //Process error or results
}()