I want my python script to wait until the user presses any key.  
How do I do that?

How to make a python script wait for a pressed key?

How to wait in a bash script for several subprocesses spawned from that script to finish, and then return exit code `!=0` when any of the subprocesses ends with code `!=0`?

Simple script:

    #!/bin/bash
    for i in `seq 0 9`; do
      doCalculations $i &amp;
    done
    wait

The above script will wait for all 10 spawned subprocesses, but it will always give exit status `0` (see `help wait`). How can I modify this script so it will discover exit statuses of spawned subprocesses and return exit code `1` when any of subprocesses ends with code `!=0`?

Is there any better solution for that than collecting PIDs of the subprocesses, wait for them in order and sum exit statuses?

How to wait in bash for several subprocesses to finish, and return exit code !=0 when any subprocess ends with code !=0?

I am trying to do something in Java and I need something to wait / delay for an amount of seconds in a while loop.

    while (true) {
        if (i == 3) {
            i = 0;
        }

        ceva[i].setSelected(true);

        // I need to wait here

        ceva[i].setSelected(false);

        // I need to wait here

        i++;
    }

I want to build a step sequencer and I&#39;m new to Java. Any suggestions?



How do I make a delay in Java?

I have a JavaScript code that I need to add a sleep/wait function to. The code I am running is already in a function, eg:

    function myFunction(time)
    {
        alert(&#39;time starts now&#39;);
        //code to make the program wait before continuing
        alert(&#39;time is up&#39;)
    }

I have heard that a possible solution might include

    setTimeout
but I am not sure how to use it in this case.

I can&#39;t use PHP, as my server does not support it, although using jQuery would be fine.

JavaScript sleep/wait before continuing

What is difference between `wait` and `sleep`?


Difference between wait and sleep

We all know that in order to invoke [`Object.wait()`][1], this call must be placed in synchronized block, otherwise an [`IllegalMonitorStateException`][2] is thrown. But **what&#39;s the reason for making this restriction?** I know that `wait()` releases the monitor, but why do we need to explicitly acquire the monitor by making particular block synchronized and then release the monitor by calling `wait()`?

What is the potential damage if it was possible to invoke `wait()` outside a synchronized block, retaining it&#39;s semantics - suspending the caller thread?


  [1]: http://docs.oracle.com/javase/7/docs/api/java/lang/Object.html#wait%28%29
  [2]: http://docs.oracle.com/javase/7/docs/api/java/lang/IllegalMonitorStateException.html

Why must wait() always be in synchronized block

I have a PowerShell 1.0 script to just open a bunch of applications. The first is a virtual machine and the others are development applications.  I want the virtual machine to finish booting before the rest of the applications are opened.

In bash I could just say `&quot;cmd1 &amp;&amp; cmd2&quot;`

This is what I&#39;ve got...

    C:\Applications\VirtualBox\vboxmanage startvm superdooper
        &amp;&quot;C:\Applications\NetBeans 6.5\bin\netbeans.exe&quot;



How to tell PowerShell to wait for each command to end before starting the next?

Can I get a complete simple scenario i.e. tutorial that suggest how this should be used, specifically with a Queue?

A simple scenario using wait() and notify() in java

Is there any builtin feature in Bash to wait for a process to finish?

The `wait` command only allows one to wait for child processes to finish.
I would like to know if there is any way to wait for any process to finish before proceeding in any script.

A mechanical way to do this is as follows but I would like to know if there is any builtin feature in Bash.

    while ps -p `cat $PID_FILE` &gt; /dev/null; do sleep 1; done

Wait for a process to finish

I am using multi-threading in java for my program.
I have run thread successfully but when I am using `Thread.wait()`, it is throwing `java.lang.IllegalMonitorStateException`.
How can I make a thread wait until it will be notified?


IllegalMonitorStateException on wait() call

I want to pause my R script until the user presses a key. 

How do I do this?

How to wait for a keypress in R?

I can&#39;t get the `.delay` method working in jQuery:

    $.delay(3000); // not working
    $(queue).delay(3000); // not working

I&#39;m using a while loop to wait until an uncontrolled changing value is greater than or equal to another and I can&#39;t find any way to hault execution for X seconds.

jQuery: Wait/Delay 1 second without executing code

    dataGridView1.Rows[x1].Cells[y1].Style.BackColor = System.Drawing.Color.Red;
    System.Threading.Thread.Sleep(1000);

İ want to wait one second before printing my grid cells with this code, but it isn&#39;t working. What can i do?

Wait one second in running program

Can anyone let me how can I make selenium wait until the time the page loads completely? I want something generic, I know I can configure WebDriverWait and call something like &#39;find&#39; to make it wait but I don&#39;t go that far. I just need to test that the page loads successfully and move on to next page to test.

I found something in .net but couldn&#39;t make it work in java ...

    IWait&lt;IWebDriver&gt; wait = new OpenQA.Selenium.Support.UI.WebDriverWait(driver, TimeSpan.FromSeconds(30.00));
    wait.Until(driver1 =&gt; ((IJavaScriptExecutor)driver).ExecuteScript(&quot;return document.readyState&quot;).Equals(&quot;complete&quot;));

Any thoughts anyone?

Selenium wait until document is ready

What is the difference between thread state WAIT and thread state BLOCKED?

The [Thread.State documentation][1]:

&gt; **Blocked**  
&gt; A thread that is blocked waiting for a monitor lock is in this state.
&gt;
&gt; **Waiting**  
&gt; A thread that is waiting indefinitely for another thread to perform a particular action is in this state


does not explain the difference to me.


  [1]: http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/Thread.State.html

Difference between WAIT and BLOCKED thread states

What is a way to simply wait for all threaded process to finish?  For example, let&#39;s say I have:

    public class DoSomethingInAThread implements Runnable{
       
        public static void main(String[] args) {
    		for (int n=0; n&lt;1000; n++) {
    			Thread t = new Thread(new DoSomethingInAThread());
    			t.start();
    		}
            // wait for all threads&#39; run() methods to complete before continuing
    	}
    	
    	public void run() {
    		// do something here
    	}
    	
    	
    }

How do I alter this so the `main()` method pauses at the comment until all threads&#39; `run()` methods exit? Thanks!

How to wait for a number of threads to complete?

I&#39;m writing an application that has 5 threads that get some information from web simultaneously and fill 5 different fields in a buffer class.  
I need to validate buffer data and store it in a database when all threads finished their job.  
How can I do this (get alerted when all threads finished their work) ?  



wait until all threads finish their work in java

I want my bash script to sleep until a specific time. So, I want a command like &quot;sleep&quot; which takes no interval but an end time and sleeps until then.

The &quot;at&quot;-daemon is not a solution, as I need to block a running script until a certain date/time.

Is there such a command?

Sleep until a specific time/date

I have a script where I launch with popen a shell command.
The problem is that the script doesn&#39;t wait until that popen command is finished and go continues right away.

    om_points = os.popen(command, &quot;w&quot;)
    .....

How can I tell to my Python script to wait until the shell command has finished?

Python popen command. Wait until the command is finished

I am using some data which is from a RESTful service in multiple pages.
So I am using angular factories for that. So, I required to get the data once from the server, and everytime I am getting the data with that defined service. Just like a global variables. Here is the sample:
	    
    var myApp =  angular.module(&#39;myservices&#39;, []);

    myApp.factory(&#39;myService&#39;, function($http) {
 		$http({method:&quot;GET&quot;, url:&quot;/my/url&quot;}).success(function(result){
			return result;
  		});
    });


In my controller I am using this service as:

    function myFunction($scope, myService) {
        $scope.data = myService;
        console.log(&quot;data.name&quot;+$scope.data.name);
    }
Its working fine for me as per my requirements.
But the problem here is, when I reloaded in my webpage the service will gets called again and requests for server. If in between some other function executes which is dependent on the &quot;defined service&quot;, It&#39;s giving the error like &quot;something&quot; is undefined. So I want to wait in my script till the service is loaded. How can I do that? Is there anyway do that in angularjs?

How to wait till the response comes from the $http request, in angularjs?

I&#39;m playing around with [Qt][1], and I want to create a simple pause between two commands. However it won&#39;t seem to let me use `Sleep(int mili);`, and I can&#39;t find any obvious wait functions.

I am basically just making a console application to test some class code which will later be included in a proper Qt GUI, so for now I&#39;m not bothered about breaking the whole event-driven model.

  [1]: https://en.wikipedia.org/wiki/Qt_%28software%29


How do I create a pause/wait function using Qt?

I&#39;m making an Ajax call which returns me some info including an image path.

I prepare all this information in my HTML which will be displayed as a kind of popup. I just toggle the visibility of by popup div from hidden to visible.

To set the position of my popup div, I have to calculate depending on the height of the image. So, I have to wait for the image to load to know its dimension before setting position and switching visibility to visible.

I tried tricks with recursion, setTimeout, complete img property, while loop... without success.

So, how can I do this? Maybe I should return dimensions in my Ajax call.



Waiting for image to load in JavaScript

I want to force a JavaScript program to wait in some particular points of its execution until a variable has changed. Is there a way to do it? I have already found an extension that is called &quot;narrative JavaScript&quot; that force the program to wait until an event to happen. Is there a way to create a new event, a &quot;variable change event&quot; for example that behaves like onclick event..

How can I make a program wait for a variable change in javascript?

I have a thread downloading data and I want to wait until the download is finished before I load the data.  Is there a standard way of doing this?

More Info:

I have a Download class that gets data from a URL (Serialized POJOs).  Download is Runnable and Observable.  It keeps track of the bytes downloaded and download size.  I have a progress bar that displays the progress to the User.   The GUI observes Download to update the progress bar.

When the POJO is downloaded I want to get it and move to the next step.  Each step has to wait for the previous to finish.  The problem is I cant think of a way to pause my application to wait for the download thread.  Once the download is finished I want to call `download.getObject()` which will return the data as an object.  I can then cast it and get on with the next download.

I have a helper class that manages the URLs for download and makes all of the calls to Download.  This call will call getObject and do the casting.  The Gui calls `helper.getUser()`. helper starts the thread running and I want it to &#39;know&#39; when it is finished so it can return the casted object. 

Any suggestions/examples? I am in the beginning stages of this design so I am willing to change it.

**Update:**

I followed [http://download.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html#get][1] and used modal to block until the thread finished.  The code was very messy and I don&#39;t like this approach.  I will keep trying to find a &#39;clean&#39; way to handle the workflow of the download processes.


  [1]: http://download.oracle.com/javase/6/docs/api/javax/swing/SwingWorker.html#get()

Java Wait for thread to finish

In a test spec, I need to click a button on a web page, and wait for the new page completely loaded.

    emailEl.sendKeys(&#39;jack&#39;);
    passwordEl.sendKeys(&#39;123pwd&#39;);
		    
    btnLoginEl.click();

    // ...Here need to wait for page complete... How?

    ptor.waitForAngular();
    expect(ptor.getCurrentUrl()).toEqual(url + &#39;abc#/efg&#39;);
		    	



Protractor : How to wait for page complete after click a button?

In C# I have the following two simple examples:

    [Test]
    public void TestWait()
    {
        var t = Task.Factory.StartNew(() =&gt;
        {
            Console.WriteLine(&quot;Start&quot;);
            Task.Delay(5000).Wait();
            Console.WriteLine(&quot;Done&quot;);
        });
        t.Wait();
        Console.WriteLine(&quot;All done&quot;);
    }

    [Test]
    public void TestAwait()
    {
        var t = Task.Factory.StartNew(async () =&gt;
        {
            Console.WriteLine(&quot;Start&quot;);
            await Task.Delay(5000);
            Console.WriteLine(&quot;Done&quot;);
        });
        t.Wait();
        Console.WriteLine(&quot;All done&quot;);
    }

The first example creates a task that prints &quot;Start&quot;, waits 5 seconds prints &quot;Done&quot; and then ends the task. I wait for the task to finish and then print &quot;All done&quot;. When I run the test it does as expected.

The second test should have the same behavior, except that the waiting inside the Task should be non-blocking due to the use of async and await. But this test just prints &quot;Start&quot; and then immediately &quot;All done&quot; and &quot;Done&quot; is never printed.

I do not know why I get this behavior :S Any help would be appreciated very much :)

await Task.Delay() vs. Task.Delay().Wait()

How can I put  a sleep function between the `TextUI.text = ....`, to wait 3 seconds between each phrase?

    public Text GuessUI;
	public Text TextUI;

    [...truncated...]

    TextUI.text = &quot;Welcome to Number Wizard!&quot;;
    TextUI.text = (&quot;The highest number you can pick is &quot; + max);
	TextUI.text = (&quot;The lowest number you can pick is &quot; + min);

I already tried various things but none have worked, such as this:

    TextUI.text = &quot;Welcome to Number Wizard!&quot;;
    yield WaitForSeconds (3);
    TextUI.text = (&quot;The highest number you can pick is &quot; + max);
    yield WaitForSeconds (3);
	TextUI.text = (&quot;The lowest number you can pick is &quot; + min);


In bash, it would be:

    echo &quot;Welcome to Number Wizard!&quot;
    sleep 3
    echo &quot;The highest number you can pick is 1000&quot;
    sleep 3
    .....

but I can&#39;t figure out how to do this in Unity with C#

How to make the script wait/sleep in a simple way in unity

I was under the impression that wait() releases all locks but I found this post which says

&quot;Invoking wait inside a synchronized method is a simple way to acquire the intrinsic lock&quot; 

Please clarify I&#39;m a bit confused.

[http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html][1]


  [1]: http://docs.oracle.com/javase/tutorial/essential/concurrency/guardmeth.html

Java : Does wait() release lock from synchronized block

**Is there a wait function in kotlin?** (I don&#39;t mean a Timer Schedule, but actually pause the execution). I have read that you can use `Thread.sleep()`. However, it doesn&#39;t work for me, because the function can&#39;t be found.



Kotlin - Wait function

I can&#39;t use `shutdown()` and `awaitTermination()` because it is possible new tasks will be added to the ThreadPoolExecutor while it is waiting.

So I&#39;m looking for a way to wait until the ThreadPoolExecutor has emptied it&#39;s queue and finished all of it&#39;s tasks without stopping new tasks from being added before that point.

If it makes any difference, this is for Android.

Thanks

**Update**: Many weeks later after revisiting this, I discovered that a modified CountDownLatch worked better for me in this case.  I&#39;ll keep the answer marked because it applies more to what I asked.


How to wait for all tasks in an ThreadPoolExecutor to finish without shutting down the Executor?

One of the first things I learned in C++ was that

    #include &lt;iostream&gt;
    int main()
    {
        std::cout&lt;&lt;&quot;Hello, World!\n&quot;;
        return 0;
    }

would simply appear and disappear extremely quickly without pause. To prevent this, I had to go to notepad, and save

    helloworld.exe
    pause

ase

    helloworld.bat

This got tedious when I needed to create a bunch of small test programs, and eventually I simply put `while(true);` at the end on most of my test programs, just so I could see the results. Is there a better wait function I can use?

Is there a decent wait function in C++?

I would like to wait some seconds between two instruction, but WITHOUT blocking the execution.

For example, `Thread.Sleep(2000)` it is not good, because it blocks execution.
 
The idea is that I call a method and then I wait X seconds (20 for example) listening for an event coming. At the end of the 20 seconds I should do some operation depending on what happened in the 20 seconds.

Wait some seconds without blocking UI execution

I&#39;m trying to make Selenium wait for an element that is dynamically added to the DOM after page load. Tried this:

    fluentWait.until(ExpectedConditions.presenceOfElement(By.id(&quot;elementId&quot;));

*In case it helps, here is `fluentWait`:*

    FluentWait fluentWait = new FluentWait&lt;&gt;(webDriver) {
        .withTimeout(30, TimeUnit.SECONDS)
        .pollingEvery(200, TimeUnit.MILLISECONDS);
    }

But it throws a `NoSuchElementException` - looks like `presenceOfElement` expects the element to be there so this is flawed. This must be bread and butter to Selenium and don&#39;t want to reinvent the wheel... could anyone suggest an alternative, ideally without rolling my own `Predicate`?

How to wait until an element is present in Selenium?

I am just having hard time to understand concept behind putting `wait()` in `Object` class.  For this questions sake consider if `wait()` and `notifyAll()` are in `Thread` class.

    class Reader extends Thread {
        Calculator c;
        public Reader(Calculator calc) {
            c = calc;
        }
    
        public void run() {
            synchronized(c) {                              //line 9
            try {
                System.out.println(&quot;Waiting for calculation...&quot;);
                c.wait();
            } catch (InterruptedException e) {}
                System.out.println(&quot;Total is: &quot; + c.total);
            }
        }

        public static void main(String [] args) {
            Calculator calculator = new Calculator();
            new Reader(calculator).start();
            new Reader(calculator).start();
            new Reader(calculator).start();
            calculator.start();
        }
    }
    
    class Calculator extends Thread {
        int total;
        public void run() {
            synchronized(this) {                     //Line 31
                for(int i=0;i&lt;100;i++) {
                    total += i;
                }
                 notifyAll();
            }
        } 
    }

My Question is that what difference it could have made? In line 9 we are acquiring lock on object c and then performing wait which satisfy the condition for wait that we need to acquire lock on the object before we use wait and so is case for notifyAll we have acquired lock on object of Calculator at line 31.


Concept behind putting wait(),notify() methods in Object class

Why are the `wait()` and `notify()` methods declared in the `Object` class, rather than the `Thread` class?

Why are wait() and notify() declared in Java&#39;s Object class?

I want to send a request to a server and process the returned value:

    private static string Send(int id)
    {
        Task&lt;HttpResponseMessage&gt; responseTask = client.GetAsync(&quot;aaaaa&quot;);
        string result = string.Empty;
        responseTask.ContinueWith(x =&gt; result = Print(x));
        responseTask.Wait(); // it doesn&#39;t wait for the completion of the response task
        return result;
    }

    private static string Print(Task&lt;HttpResponseMessage&gt; httpTask)
    {
        Task&lt;string&gt; task = httpTask.Result.Content.ReadAsStringAsync();
        string result = string.Empty;
        task.ContinueWith(t =&gt;
        {
            Console.WriteLine(&quot;Result: &quot; + t.Result);
            result = t.Result;
        });
        task.Wait();  // it does wait
        return result;
    }

Am I using `Task` correctly? I don&#39;t think so because the `Send()` method returns `string.Empty` every time, while `Print` returns the correct value.

What am I doing wrong? How do I get the correct result from a server?

How do I wait until Task is finished in C#?

How can the `wait()` and `notify()` methods be called on Objects that are not Threads? That doesn&#39;t really make sense, does it?

Surely, it must make sense, however, because the two methods are available for all Java objects. Can someone provide an explanation? I am having trouble understanding how to communicate between threads using `wait()` and `notify()`.


All Wait Solutions on Gang of Coders

Total of 37 Wait Solutions