Programs & Examples On #Monitor

Monitor is component for Monitoring. It is the act of looking on the processes or systems for performance, supervision and surveillance.

Semaphore vs. Monitors - what's the difference?

One Line Answer:

Monitor: controls only ONE thread at a time can execute in the monitor. (need to acquire lock to execute the single thread)

Semaphore: a lock that protects a shared resource. (need to acquire the lock to access resource)

How can I monitor the thread count of a process on linux?

cat /proc/<PROCESS_PID>/status | grep Threads

Can Json.NET serialize / deserialize to / from a stream?

I arrived at this question looking for a way to stream an open ended list of objects onto a System.IO.Stream and read them off the other end, without buffering the entire list before sending. (Specifically I'm streaming persisted objects from MongoDB over Web API.)

@Paul Tyng and @Rivers did an excellent job answering the original question, and I used their answers to build a proof of concept for my problem. I decided to post my test console app here in case anyone else is facing the same issue.

using System;
using System.Diagnostics;
using System.IO;
using System.IO.Pipes;
using System.Threading;
using System.Threading.Tasks;
using Newtonsoft.Json;

namespace TestJsonStream {
    class Program {
        static void Main(string[] args) {
            using(var writeStream = new AnonymousPipeServerStream(PipeDirection.Out, HandleInheritability.None)) {
                string pipeHandle = writeStream.GetClientHandleAsString();
                var writeTask = Task.Run(() => {
                    using(var sw = new StreamWriter(writeStream))
                    using(var writer = new JsonTextWriter(sw)) {
                        var ser = new JsonSerializer();
                        for(int i = 0; i < 25; i++) {
                            ser.Serialize(writer, new DataItem { Item = i });
                var readTask = Task.Run(() => {
                    var sw = new Stopwatch();
                    using(var readStream = new AnonymousPipeClientStream(pipeHandle))
                    using(var sr = new StreamReader(readStream))
                    using(var reader = new JsonTextReader(sr)) {
                        var ser = new JsonSerializer();
                        if(!reader.Read() || reader.TokenType != JsonToken.StartArray) {
                            throw new Exception("Expected start of array");
                        while(reader.Read()) {
                            if(reader.TokenType == JsonToken.EndArray) break;
                            var item = ser.Deserialize<DataItem>(reader);
                            Console.WriteLine("[{0}] Received item: {1}", sw.Elapsed, item);
                Task.WaitAll(writeTask, readTask);

        class DataItem {
            public int Item { get; set; }
            public override string ToString() {
                return string.Format("{{ Item = {0} }}", Item);

Note that you may receive an exception when the AnonymousPipeServerStream is disposed, I ignored this as it isn't relevant to the problem at hand.

UIView background color in Swift

Try This, It worked like a charm! for me,

The simplest way to add backgroundColor programmatically by using ColorLiteral.

You need to add the property ColorLiteral, Xcode will prompt you with a whole list of colors in which you can choose any color. The advantage of doing this is we use lesser code, add HEX values or RGB. You will also get the recently used colors from the storyboard.

Follow steps ,

1) Add below line of code in viewDidLoad() ,

self.view.backgroundColor = ColorLiteral

and clicked on enter button .

2) Display square box next to =

enter image description here

3) When Clicked on Square Box Xcode will prompt you with a whole list of colors which you can choose any colors also you can set HEX values or RGB

enter image description here

4) You can successfully set the colors .

enter image description here

Hope this will help some one to set backgroundColor in different ways.

Concatenate two NumPy arrays vertically

If the actual problem at hand is to concatenate two 1-D arrays vertically, and we are not fixated on using concatenate to perform this operation, I would suggest the use of np.column_stack:

In []: a = np.array([1,2,3])
In []: b = np.array([4,5,6])
In []: np.column_stack((a, b))
array([[1, 4],
       [2, 5],
       [3, 6]])

What's the best way to override a user agent CSS stylesheet rule that gives unordered-lists a 1em margin?

If You Are Able to Edit the Offending Stylesheet

If the user-agent stylesheet's style is causing problems for the browser it's supposed to fix, then you could try removing the offending style and testing that to ensure it doesn't have any unexpected adverse effects elsewhere.

If it doesn't, use the modified stylesheet. Fixing browser quirks is what these sheets are for - they fix issues, they aren't supposed to introduce new ones.

If You Are Not Able to Edit the Offending Stylesheet

If you're unable to edit the stylesheet that contains the offending line, you may consider using the !important keyword.

An example:

.override {
    border: 1px solid #000 !important;

.a_class {
    border: 2px solid red;

And the HTML:

<p class="a_class">content will have 2px red border</p>
<p class="override a_class">content will have 1px black border</p>

Live example

Try to use !important only where you really have to - if you can reorganize your styles such that you don't need it, this would be preferable.

jQuery show/hide options from one select drop down, when option on other select dropdown is slected

And in 2016.....I do this (which works in all browsers and does not create "illegal" html).

For the drop-down select that is to show/hide different values add that value as a data attribute.

<select id="animal">
    <option value="1" selected="selected">Dog</option>
    <option value="2">Cat</option>
<select id="name">
    <option value=""></option>
    <option value="1" data-attribute="1">Rover</option>
    <option value="2" selected="selected" data-attribute="1">Lassie</option>
    <option value="3" data-attribute="1">Spot</option>
    <option value="4" data-attribute="2">Tiger</option>
    <option value="5" data-attribute="2">Fluffy</option>

Then in your jQuery add a change event to the first drop-down select to filter the second drop-down.

$("#animal").change( function() {
    filterSelectOptions($("#name"), "data-attribute", $(this).val());

And the magic part is this little jQuery utility.

function filterSelectOptions(selectElement, attributeName, attributeValue) {
    if ("currentFilter") != attributeValue) {"currentFilter", attributeValue);
        var originalHTML ="originalHTML");
        if (originalHTML)
        else {
            var clone = selectElement.clone();
  "originalHTML", clone.html());
        if (attributeValue) {
            selectElement.children("option:not([" + attributeName + "='" + attributeValue + "'],:not([" + attributeName + "]))").remove();

This little gem tracks the current filter, if different it restores the original select (all items) and then removes the filtered items. If the filter item is empty we see all items.

Gson library in Android Studio

Use gradle dependencies to get the Gson in your project. Your application build.gradle should look like this-

dependencies {
  implementation ''

<hr> tag in Twitter Bootstrap not functioning correctly?

It is because Bootstrap's DEFAULT CSS for <hr /> is ::

hr {
    margin-top: 20px;
    margin-bottom: 20px;
    border: 0;
    border-top: 1px solid #eeeeee;

it creates 40px gap between those two lines

so if you want to change any particular <hr /> margin style in your page you may try something like this ::

<hr style="margin-bottom:5px !important; margin-top:5px !important; " />

if you want to change appearance/other styles of any particular <hr /> in your page like color and border type or thickness the you may try something like :

<hr style="border-top: 1px dotted #000000 !important; " />

for all <hr /> in your page

   hr {
       border-top: 1px dotted #000000 !important;
       margin-bottom:5px !important; 
       margin-top:5px !important;

How to append the output to a file?

you can append the file with >> sign. It insert the contents at the last of the file which we are using.e.g if file let its name is myfile contains xyz then cat >> myfile abc ctrl d

after the above process the myfile contains xyzabc.

Get mouse wheel events in jQuery?

    $('#foo').bind('mousewheel', function(e){
        if(e.originalEvent.wheelDelta /120 > 0) {
            console.log('scrolling up !');
            console.log('scrolling down !');

Writing .csv files from C++

If you wirte to a .csv file in C++ - you should use the syntax of :

myfile <<" %s; %s; %d", string1, string2, double1 <<endl;

This will write the three variables (string 1&2 and double1) into separate columns and leave an empty row below them. In excel the ; means the new row, so if you want to just take a new row - you can alos write a simple ";" before writing your new data into the file. If you don't want to have an empty row below - you should delete the endl and use the:"result.csv", std::ios::out | std::ios::app);

syntax when opening the .csv file (example the result.csv). In this way next time you write something into your result.csv file - it will write it into a new row directly below the last one - so you can easily manage a for cycle if you would like to.

Sql select rows containing part of string

You can use the LIKE operator to compare the content of a T-SQL string, e.g.

SELECT * FROM [table] WHERE [field] LIKE '%stringtosearchfor%'.

The percent character '%' is a wild card- in this case it says return any records where [field] at least contains the value "stringtosearchfor".

Ubuntu: Using curl to download an image

For ones who got permission denied for saving operation, here is the command that worked for me:

$ curl --output py.png

iPad/iPhone hover problem causes the user to double click a link

I had the following problems with the existing solutions, and found something that seems to solve all of them. This assumes you're aiming for something cross browser, cross device, and don't want device sniffing.

The problems this solves

Using just touchstart or touchend:

  • Causes the event to fire when people are trying to scroll past the content and just happened to have their finger over this element when they starting swiping - triggering the action unexpectedly.
  • May cause the event to fire on longpress, similar to right click on desktop. For example, if your click event goes to URL X, and the user longpresses to open X in a new tab, the user will be confused to find X open in both tabs. On some browsers (e.g. iPhone) it may even prevent the long press menu from appearing.

Triggering mouseover events on touchstart and mouseout on touchmove has less serious consequences, but does interfere with the usual browser behaviour, for example:

  • A long press would trigger a mouseover that never ends.
  • Many Android browsers treat the location of the finger on touchstart like a mouseover, which is mouseouted on the next touchstart. One way to see mouseover content in Android is therefore to touch the area of interest and wiggle your finger, scrolling the page slightly. Treating touchmove as mouseout breaks this.

The solution

In theory, you could just add a flag with touchmove, but iPhones trigger touchmove even if there's no movement. In theory, you could just compare the touchstart and touchend event pageX and pageY but on iPhones, there's no touchend pageX or pageY.

So unfortunately to cover all bases it does end up a little more complicated.

$el.on('touchstart', function(e){
    $'tstartE', e);
        // store values, not reference, since touch obj will change
        var touch = e.originalEvent.targetTouches[0];
        $'tstartT',{ clientX: touch.clientX, clientY: touch.clientY } );
$el.on('touchmove', function(e){
        $'tstartM', event.originalEvent.targetTouches[0]);

$el.on('click touchend', function(e){
    var oldE = $'tstartE');
    if( oldE && oldE.timeStamp + 1000 < e.timeStamp ) {
    if( $'iosTouchM') && $'tstartT') ){
        var start = $'tstartT'), end = $'tstartM');
        if( start.clientX != end.clientX || start.clientY != end.clientY ){
            $'tstartT', false);
            $'tstartM', false);

In theory, there are ways to get the exact time used for a longpress instead of just using 1000 as an approximation, but in practice it's not that simple and it's best to use a reasonable proxy.

How to check string length and then select substring in Sql Server

To conditionally check the length of the string, use CASE.

SELECT  CASE WHEN LEN(comments) <= 60 
             THEN comments
             ELSE LEFT(comments, 60) + '...'
        END  As Comments
FROM    myView

how to update spyder on anaconda

Use this conda install spyder=4.0.0 This will not mess up your anaconda dependencies.

How to find the logs on android studio?


Create numpy matrix filled with NaNs

Another option is to use numpy.full, an option available in NumPy 1.8+

a = np.full([height, width, 9], np.nan)

This is pretty flexible and you can fill it with any other number that you want.

How do I remove the height style from a DIV using jQuery?


I like using this, because it's symmetric with how you explicitly used .height(val) to set it in the first place, and works across browsers.

No visible cause for "Unexpected token ILLEGAL"

I had the same problem on my mac and found it was because the Mac was replacing the standard quotes with curly quotes which are illegal javascript characters.

To fix this I had to change the settings on my mac System Preferences=>Keyboard=>Text(tab) uncheck use smart quotes and dashes (default was checked).

Get value (String) of ArrayList<ArrayList<String>>(); in Java

The right way to iterate on a list inside list is:

//iterate on the general list
for(int i = 0 ; i < collection.size() ; i++) {
    ArrayList<String> currentList = collection.get(i);
    //now iterate on the current list
    for (int j = 0; j < currentList.size(); j++) {
        String s = currentList.get(1);

Owl Carousel Won't Autoplay

Setting autoPlay: true didn't work for me. But on setting autoPlay: 5000 it worked.

Adding timestamp to a filename with mv in BASH

A single line method within bash works like this.

[some out put] >$(date "+%Y.%m.%d-%H.%M.%S").ver

will create a file with a timestamp name with ver extension. A working file listing snap shot to a date stamp file name as follows can show it working.

find . -type f -exec ls -la {} \; | cut -d ' ' -f 6- >$(date "+%Y.%m.%d-%H.%M.%S").ver

Of course

cat somefile.log > $(date "+%Y.%m.%d-%H.%M.%S").ver

or even simpler

ls > $(date "+%Y.%m.%d-%H.%M.%S").ver

SQL Plus change current directory

I don't think that you can change the directory in SQL*Plus.

Instead of changing directory, you can use @@filename, which reads in another script whose location is relative to the directory the current script is running in. For example, if you have two scripts


then script1.sql can run script2.sql if it contains the line


See this for more info about @@.

Disable submit button on form submit

Disabled controls do not submit their values which does not help in knowing if the user clicked save or delete.

So I store the button value in a hidden which does get submitted. The name of the hidden is the same as the button name. I call all my buttons by the name of button.

E.g. <button type="submit" name="button" value="save">Save</button>

Based on this I found here. Just store the clicked button in a variable.

    var submitButton$;

    $(document).on('click', ":submit", function (e)
        // you may choose to remove disabled from all buttons first here.
        submitButton$ = $(this);

    $(document).on('submit', "form", function(e)
        var form$ = $(this);
        var hiddenButton$ = $('#button', form$);
        if (IsNull(hiddenButton$))
            // add the hidden to the form as needed
            hiddenButton$ = $('<input>')
                .attr({ type: 'hidden', id: 'button', name: 'button' })
        hiddenButton$.attr('value', submitButton$.attr('value'));
        submitButton$.attr("disabled", "disabled");

Here is my IsNull function. Use or substitue your own version for IsNull or undefined etc.

function IsNull(obj)
    var is;
    if (obj instanceof jQuery)
        is = obj.length <= 0;
        is = obj === null || typeof obj === 'undefined' || obj == "";

    return is;

Redirect to external URL with return in laravel

You should be able to redirect to the url like this

return Redirect::to($url);

You can read about Redirects in the Laravel docs here.

How to make Python script run as service?

I offer two recommendations:


1) Install the supervisor package (more verbose instructions here):

sudo apt-get install supervisor

2) Create a config file for your daemon at /etc/supervisor/conf.d/flashpolicyd.conf:


3) Restart supervisor to load your new .conf

supervisorctl update
supervisorctl restart flashpolicyd

systemd (if currently used by your Linux distro)

Description=My Python daemon

ExecStart=/usr/bin/python3 /opt/project/


Place this file into /etc/systemd/system/my_daemon.service and enable it using systemctl daemon-reload && systemctl enable my_daemon && systemctl start my_daemon --no-block.

To view logs:

systemctl status my_daemon

A completely free agile software process tool

You can check out It's free for now because it's in beta and they say there is no time limit. It behaves very similar to AgileZen

I second the google doc, or you could use an online collaborative board that multiple people can edit.

Or you can host a more robust excel doc in skydrive from MS. I haven't tried that yet. is another one that I am playing with currently. It has unlimited collaborators, though I think you would probably have to invite them everytime?? with a free account.

Hope that helps!

how to hide the content of the div in css

#mybox:hover { display: none; }
#mybox:hover { visibility: hidden; }
#mybox:hover { background: none; }
#mybox:hover { color: green; }

though it should be noted that IE6 and below wont listen to the hover when it's not on an A tag. For that you have to incorporate JavaScript to add a class to the div during the hover.

What does it mean "No Launcher activity found!"

MAIN will decide the first activity that will used when the application will start. Launcher will add application in the application dashboard.

If you have them already and you are still getting the error message but maybe its because you might be using more than more category or action in an intent-filter. In an intent filter there can only be one such tag. To add another category, put it in another intent filter, like the following

            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />

             TODO - Add necessary intent filter information so that this
                Activity will accept Intents with the
                action "android.intent.action.VIEW" and with an "http"
                schemed URL
            <action android:name="android.intent.action.VIEW" />
            <data android:scheme="http" />
            <category android:name="android.intent.category.BROWSABLE" />

"Could not find bundler" error

If you're using rbenv running rbenv rehash can solve this after you've installed bundler and are still getting the issue.

opening a window form from another form programmatically

You just need to use Dispatcher to perform graphical operation from a thread other then UI thread. I don't think that this will affect behavior of the main form. This may help you : Accessing UI Control from BackgroundWorker Thread

How to terminate script execution when debugging in Google Chrome?

You can pause on any XHR pattern which I find very useful during debugging these kind of scenarios.

For example I have given breakpoint on an URL pattern containing "/"

enter image description here

How do I access my webcam in Python?

John Montgomery's, answer is great, but at least on Windows, it is missing the line




Without it, the camera resource is locked, and can not be captured again before the python console is killed.

unix - count of columns in file

Proper pure way

Under bash, you could simply:

IFS=\| read -ra headline <stores.dat
echo ${#headline[@]}

A lot quicker as without forks, and reusable as $headline hold the full head line. You could, for sample:

printf " - %s\n" "${headline[@]}"
 - sid
 - storeNo
 - latitude
 - longitude

Nota This syntax will drive correctly spaces and others characters in column names.

Alternative: strong binary checking for max columns on each rows

What if some row do contain some extra columns?

This command will search for bigger line, counting separators:

tr -dc $'\n|' <stores.dat |wc -L

There are max 3 separators, then 4 fields.

How to remove first and last character of a string?


def spaceMeOut(str1):





def spaceMeOut(str1):





Python class returning value

class MyClass():
    def __init__(self, a, b):
        self.value1 = a
        self.value2 = b

    def __call__(self):
        return [self.value1, self.value2]


>>> x = MyClass('foo','bar')
>>> x()
['foo', 'bar']

How can I insert into a BLOB column from an insert statement in sqldeveloper?

To insert a VARCHAR2 into a BLOB column you can rely on the function utl_raw.cast_to_raw as next:

insert into mytable(id, myblob) values (1, utl_raw.cast_to_raw('some magic here'));

It will cast your input VARCHAR2 into RAW datatype without modifying its content, then it will insert the result into your BLOB column.

More details about the function utl_raw.cast_to_raw

How to save the contents of a div as a image?

Do something like this:

A <div> with ID of #imageDIV, another one with ID #download and a hidden <div> with ID #previewImage.

Include the latest version of jquery, and jspdf.debug.js from the jspdf CDN

Then add this script:

var element = $("#imageDIV"); // global variable
var getCanvas; // global variable
  html2canvas(element, {
    onrendered: function (canvas) {
      getCanvas = canvas;
$("#download").on('click', function () {
  var imgageData = getCanvas.toDataURL("image/png");
  // Now browser starts downloading it instead of just showing it
  var newData = imageData.replace(/^data:image\/png/, "data:application/octet-stream");
  $("#download").attr("download", "image.png").attr("href", newData);

The div will be saved as a PNG on clicking the #download

How to copy directories with spaces in the name

After some trial and error and observing the results (in other words, I hacked it), I got it to work.

Quotes ARE required to use a path name with spaces. The trick is there MUST be a space after the path names before the closing this...

robocopy "C:\Source Path " "C:\Destination Path " /option1 /option2...

This almost seems like a bug and certainly not very intuitive.

Todd K.

How to remove border from specific PrimeFaces p:panelGrid?

for me only the following code works

.noBorder tr {
border-width: 0 ;
.ui-panelgrid td{
    border-width: 0

<p:panelGrid id="userFormFields" columns="2" styleClass="noBorder" >

Check if file is already open

    //  OR NOT (not for .txt files)

    //  the file we want to check
    String fileName = "C:\\Text.xlsx";
    File file = new File(fileName);

    // try to rename the file with the same name
    File sameFileName = new File(fileName);

        // if the file is renamed
        System.out.println("file is closed");    
        // if the file didnt accept the renaming operation
        System.out.println("file is opened");

How to change the server port from 3000?

If you don't have bs-config.json, you can change the port inside the lite-server module. Go to node_modules/lite-server/lib/config-defaults.js in your project, then add the port in "modules.export" like this.

module.export {
    port :8000, // to any available port

Then you can restart the server.

How to Set a Custom Font in the ActionBar Title?

No custom textview is required!

First, disable the title in the toobar in your java code : getSupportActionBar().setDisplayShowTitleEnabled(false);

Then, simply add a TextView inside the toolbar :


        android:fontFamily="@font/roboto" />


Split a large pandas dataframe

I also experienced np.array_split not working with Pandas DataFrame my solution was to only split the index of the DataFrame and then introduce a new column with the "group" label:

indexes = np.array_split(df.index,N, axis=0)
for i,index in enumerate(indexes):
   df.loc[index,'group'] = i

This makes grouby operations very convenient for instance calculation of mean value of each group:


What is Java EE?

J2EE traditionally referred to products and standards released by Sun. For example if you were developing a standard J2EE web application, you would be using EJBs, Java Server Faces, and running in an application server that supports the J2EE standard. However since there is such a huge open source plethora of libraries and products that do the same jobs as well as (and many will argue better) then these Sun offerings, the day to day meaning of J2EE has migrated into referring to these as well (For instance a Spring/Tomcat/Hibernate solution) in many minds.

This is a great book in my opinion that discusses the 'open source' approach to J2EE

A html space is showing as %2520 instead of %20

When you are trying to visit a local filename through firefox browser, you have to force the file:\\\ protocol ( or else firefox will encode your space TWICE. Change the html snippet from this:

<img src="C:\Documents and Settings\screenshots\Image01.png"/>

to this:

<img src="file:\\\C:\Documents and Settings\screenshots\Image01.png"/>

or this:

<img src="file://C:\Documents and Settings\screenshots\Image01.png"/>

Then firefox is notified that this is a local filename, and it renders the image correctly in the browser, correctly encoding the string once.

Helpful link:

int to string in MySQL

Try it using CONCAT

CONCAT('','%', CAST( AS CHAR(25)), '%','/more')

How to exit if a command failed?

The other answers have covered the direct question well, but you may also be interested in using set -e. With that, any command that fails (outside of specific contexts like if tests) will cause the script to abort. For certain scripts, it's very useful.

Implement division with bit-wise operator

For integers:

public class Division {

    public static void main(String[] args) {
        System.out.println("Division: " + divide(100, 9));

    public static int divide(int num, int divisor) {
        int sign = 1;
        if((num > 0 && divisor < 0) || (num < 0 && divisor > 0))
            sign = -1;

        return divide(Math.abs(num), Math.abs(divisor), Math.abs(divisor)) * sign;

    public static int divide(int num, int divisor, int sum) {
        if (sum > num) {
            return 0;

        return 1 + divide(num, divisor, sum + divisor);

How to convert integer to string in C?

Use sprintf():

int someInt = 368;
char str[12];
sprintf(str, "%d", someInt);

All numbers that are representable by int will fit in a 12-char-array without overflow, unless your compiler is somehow using more than 32-bits for int. When using numbers with greater bitsize, e.g. long with most 64-bit compilers, you need to increase the array size—at least 21 characters for 64-bit types.

Get value of multiselect box using jQuery or pure JS

This got me the value and text of the selected options for the jQuery multiselect.js plugin:

    afterSelect: function(){
        var selections = [];
        $("#selectBox option:selected").each(function(){
            var optionValue = $(this).val();
            var optionText = $(this).text();
            // collect all values

        // use array "selections" here.. 

very usefull if you need it for your "onChange" event ;)

How to add days to the current date?

From the SQL Server 2017 official documentation:


If you would like to remove the time part of the GETDATE function, you can do:


Oracle 'Partition By' and 'Row_Number' keyword

That selects the row number per country code, account, and currency. So, the rows with country code "US", account "XYZ" and currency "$USD" will each get a row number assigned from 1-n; the same goes for every other combination of those columns in the result set.

This query is kind of funny, because the order by clause does absolutely nothing. All the rows in each partition have the same country code, account, and currency, so there's no point ordering by those columns. The ultimate row numbers assigned in this particular query will therefore be unpredictable.

Hope that helps...

Vue component event after render

updated() should be what you're looking for:

Called after a data change causes the virtual DOM to be re-rendered and patched.

The component’s DOM will have been updated when this hook is called, so you can perform DOM-dependent operations here.

How to define an empty object in PHP

I want to point out that in PHP there is no such thing like empty object in sense:

$obj = new stdClass();
var_dump(empty($obj)); // bool(false)

but of course $obj will be empty.

On other hand empty array mean empty in both cases

$arr = array();

Quote from changelog function empty

Objects with no properties are no longer considered empty.

How do you stylize a font in Swift?

You can set custom font in two ways : design time and run-time.

  1. First you need to download required font (.ttf file format). Then, double click on the file to install it.

  2. This will show a pop-up. Click on 'install font' button.

Screenshot 1

  1. This will install the font and will appear in 'Fonts' window.

Screenshot 2

  1. Now, the font is installed successfully. Drag and drop the custom font in your project. While doing this make sure that 'Add to targets' is checked.

Screenshot 3

  1. You need to make sure that this file is also added into 'Copy Bundle Resources' present in Build Phases of Targets of your project.

Screenshot 4

  1. After this you need to add this font in Info.plist of your project. Create a new key with 'Font Provided by application' with type as Array. Add a the font as an element with type String in Array.

Screenshot 5

A. Design mode :

  1. Select the label from Storyboard file. Goto Font attribute present in Attribute inspector of Utilities.

Screenshot 6

  1. Click on Font and select 'Custom font'

Screenshot 7

  1. From Family section select the custom font you have installed.

Screenshot 8

  1. Now you can see that font of label is set to custom font.

Screenshot 9

B. Run-time mode :

 self.lblWelcome.font = UIFont(name: "BananaYeti-Extrabold Trial", size: 16)

It seems that run-time mode doesn't work for dynamically formed string like

self.lblWelcome.text = "Welcome, " + fullname + "!"

Note that in above case only design-time approach worked correctly for me.

Alter a SQL server function to accept new optional parameter

I have found the EXECUTE command as suggested here T-SQL - function with default parameters to work well. With this approach there is no 'DEFAULT' needed when calling the function, you just omit the parameter as you would with a stored procedure.

invalid use of non-static member function

The simplest fix is to make the comparator function be static:

static int comparator (const Bar & first, const Bar & second);

When invoking it in Count, its name will be Foo::comparator.

The way you have it now, it does not make sense to be a non-static member function because it does not use any member variables of Foo.

Another option is to make it a non-member function, especially if it makes sense that this comparator might be used by other code besides just Foo.

Center align a column in twitter bootstrap

With bootstrap 3 the best way to go about achieving what you want is ...with offsetting columns. Please see these examples for more detail:

In short, and without seeing your divs here's an example what might help, without using any custom classes. Just note how the "col-6" is used and how half of that is 3 the "offset-3" is used. Splitting equally will allow the centered spacing you're going for:

<div class="container">
<div class="col-sm-6 col-sm-offset-3">
your centered, floating column

How do I specify different Layouts in the ASP.NET MVC 3 razor ViewStart file?

One more method is to Define the Layout inside the View:

    Layout = "~/Views/Shared/_MyAdminLayout.cshtml";

More Ways to do, can be found here, hope this helps someone.

How do you determine the size of a file in C?


The POSIX standard has its own method to get file size.
Include the sys/stat.h header to use the function.


  • Get file statistics using stat(3).
  • Obtain the st_size property.


Note: It limits the size to 4GB. If not Fat32 filesystem then use the 64bit version!

#include <stdio.h>
#include <sys/stat.h>

int main(int argc, char** argv)
    struct stat info;
    stat(argv[1], &info);

    // 'st' is an acronym of 'stat'
    printf("%s: size=%ld\n", argv[1], info.st_size);
#include <stdio.h>
#include <sys/stat.h>

int main(int argc, char** argv)
    struct stat64 info;
    stat64(argv[1], &info);

    // 'st' is an acronym of 'stat'
    printf("%s: size=%ld\n", argv[1], info.st_size);

ANSI C (standard)

The ANSI C doesn't directly provides the way to determine the length of the file.
We'll have to use our mind. For now, we'll use the seek approach!


  • Seek the file to the end using fseek(3).
  • Get the current position using ftell(3).


#include <stdio.h>

int main(int argc, char** argv)
    FILE* fp = fopen(argv[1]);
    int f_size;

    fseek(fp, 0, SEEK_END);
    f_size = ftell(fp);
    rewind(fp); // to back to start again

    printf("%s: size=%ld", (unsigned long)f_size);

If the file is stdin or a pipe. POSIX, ANSI C won't work.
It will going return 0 if the file is a pipe or stdin.

Opinion: You should use POSIX standard instead. Because, it has 64bit support.

Reading file using relative path in python project

This worked for me.

with open('data/test.csv') as f:


Setting the zoom level for a MKMapView

A simple Swift implementation, if you use outlets.

@IBOutlet weak var mapView: MKMapView! {
    didSet {
        let noLocation = CLLocationCoordinate2D()
        let viewRegion = MKCoordinateRegionMakeWithDistance(noLocation, 500, 500)
        self.mapView.setRegion(viewRegion, animated: false)

Based on @Carnal's answer.

How to delete a cookie using jQuery?

it is the problem of misunderstand of cookie. Browsers recognize cookie values for not just keys also compare the options path & domain. So Browsers recognize different value which cookie values that key is 'name' with server setting option(path='/'; domain='') and key is 'name' with no option.

How do you push just a single Git branch (and no other branches)?

Minor update on top of Karthik Bose's answer - you can configure git globally, to affect all of your workspaces to behave that way:

git config --global push.default upstream

How to remove folders with a certain name

This also works - it will remove all the folders called "a" and their contents:

rm -rf `find -type d -name a`

How to provide password to a command that prompts for one in bash?

Secure commands will not allow this, and rightly so, I'm afraid - it's a security hole you could drive a truck through.

If your command does not allow it using input redirection, or a command-line parameter, or a configuration file, then you're going to have to resort to serious trickery.

Some applications will actually open up /dev/tty to ensure you will have a hard time defeating security. You can get around them by temporarily taking over /dev/tty (creating your own as a pipe, for example) but this requires serious privileges and even it can be defeated.

Cycles in family tree software

Here's the problem with family trees: they are not trees. They are directed acyclic graphs or DAGs. If I understand the principles of the biology of human reproduction correctly, there will not be any cycles.

As far as I know, even the Christians accept marriages (and thus children) between cousins, which will turn the family tree into a family DAG.

The moral of the story is: choose the right data structures.

Differences between ConstraintLayout and RelativeLayout

The real question to ask is, is there any reason to use any layout other than a constraint layout? I believe the answer might be no.

To those insisting they are aimed at novice programmers or the like, they should provide some reason for them to be inferior to any other layout.

Constraints layouts are better in every way (They do cost like 150k in APK size.). They are faster, they are easier, they are more flexible, they react better to changes, they fix the problems when items go away, they conform better to radically different screen types and they don't use a bunch of nested loop with that long drawn out tree structure for everything. You can put anything anywhere, with respect to anything, anywhere.

They were a bit screwy back in mid 2016, where the visual layout editor just wasn't good enough, but they are to the point that if you are having a layout at all, you might want to seriously consider using a constraint layout, even when it does the same thing as a RelativeLayout, or even a simple LinearLayout. FrameLayouts clearly still have their purpose. But, I can't see building anything else at this point. If they started with this they wouldn't have added anything else.

How to reset radiobuttons in jQuery so that none is checked

I know this is old and that this is a little off topic, but supposing you wanted to uncheck only specific radio buttons in a collection:

      if($(this).val() !== "1"){_x000D_
<script src=""></script>_x000D_
<input id="radio1" type="radio" name="correctAnswer" value="1">1</input>_x000D_
<input id="radio2" type="radio" name="correctAnswer" value="2">2</input>_x000D_
<input id="radio3" type="radio" name="correctAnswer" value="3">3</input>_x000D_
<input id="radio4" type="radio" name="correctAnswer" value="4">4</input>_x000D_
<input type="button" id="go" value="go">

And if you are dealing with a radiobutton list, you can use the :checked selector to get just the one you want.

<script src=""></script>
<input id="radio1" type="radio" name="correctAnswer" value="1">1</input>
<input id="radio2" type="radio" name="correctAnswer" value="2">2</input>
<input id="radio3" type="radio" name="correctAnswer" value="3">3</input>
<input id="radio4" type="radio" name="correctAnswer" value="4">4</input>
<input type="button" id="go" value="go">

Keystore type: which one to use?

There are a few more types than what's listed in the standard name list you've linked to. You can find more in the cryptographic providers documentation. The most common are certainly JKS (the default) and PKCS12 (for PKCS#12 files, often with extension .p12 or sometimes .pfx).

JKS is the most common if you stay within the Java world. PKCS#12 isn't Java-specific, it's particularly convenient to use certificates (with private keys) backed up from a browser or coming from OpenSSL-based tools (keytool wasn't able to convert a keystore and import its private keys before Java 6, so you had to use other tools).

If you already have a PKCS#12 file, it's often easier to use the PKCS12 type directly. It's possible to convert formats, but it's rarely necessary if you can choose the keystore type directly.

In Java 7, PKCS12 was mainly useful as a keystore but less for a truststore (see the difference between a keystore and a truststore), because you couldn't store certificate entries without a private key. In contrast, JKS doesn't require each entry to be a private key entry, so you can have entries that contain only certificates, which is useful for trust stores, where you store the list of certificates you trust (but you don't have the private key for them).

This has changed in Java 8, so you can now have certificate-only entries in PKCS12 stores too. (More details about these changes and further plans can be found in JEP 229: Create PKCS12 Keystores by Default.)

There are a few other keystore types, perhaps less frequently used (depending on the context), those include:

  • PKCS11, for PKCS#11 libraries, typically for accessing hardware cryptographic tokens, but the Sun provider implementation also supports NSS stores (from Mozilla) through this.
  • BKS, using the BouncyCastle provider (commonly used for Android).
  • Windows-MY/Windows-ROOT, if you want to access the Windows certificate store directly.
  • KeychainStore, if you want to use the OSX keychain directly.

how to realize countifs function (excel) in R

Given a dataset

df <- data.frame( sex = c('M', 'M', 'F', 'F', 'M'), 
                  occupation = c('analyst', 'dentist', 'dentist', 'analyst', 'cook') )

you can subset rows

df[df$sex == 'M',] # To get all males
df[df$occupation == 'analyst',] # All analysts


If you want to get number of rows, just call the function nrow such as

nrow(df[df$sex == 'M',])

executing a function in sql plus

  x number;
  x := myfunc(myargs);


select myfunc(myargs) from dual;

Does height and width not apply to span?

Inspired from @Hamed, I added the following and it worked for me:

display: inline-block; overflow: hidden; 

Call static methods from regular ES6 class methods

Both ways are viable, but they do different things when it comes to inheritance with an overridden static method. Choose the one whose behavior you expect:

class Super {
  static whoami() {
    return "Super";
  lognameA() {
  lognameB() {
class Sub extends Super {
  static whoami() {
    return "Sub";
new Sub().lognameA(); // Super
new Sub().lognameB(); // Sub

Referring to the static property via the class will be actually static and constantly give the same value. Using this.constructor instead will use dynamic dispatch and refer to the class of the current instance, where the static property might have the inherited value but could also be overridden.

This matches the behavior of Python, where you can choose to refer to static properties either via the class name or the instance self.

If you expect static properties not to be overridden (and always refer to the one of the current class), like in Java, use the explicit reference.

How to get the background color of an HTML element?

With jQuery:


With prototype:


With pure JS:


"Exception has been thrown by the target of an invocation" error (mscorlib)

I know its kind of odd but I experienced this error for a c# application and finally I found out the problem is the Icon of the form! when I changed it everything just worked fine.

I should say that I had this error just in XP not in 7 or 8 .

MySQL direct INSERT INTO with WHERE clause

Example of how to perform a INSERT INTO SELECT with a WHERE clause.

INSERT INTO #test2 (id) SELECT id FROM #test1 WHERE id > 2

Multiple ping script in Python

To ping several hosts at once you could use subprocess.Popen():

#!/usr/bin/env python3
import os
import time
from subprocess import Popen, DEVNULL

p = {} # ip -> process
for n in range(1, 100): # start ping processes
    ip = "127.0.0.%d" % n
    p[ip] = Popen(['ping', '-n', '-w5', '-c3', ip], stdout=DEVNULL)
    #NOTE: you could set stderr=subprocess.STDOUT to ignore stderr also

while p:
    for ip, proc in p.items():
        if proc.poll() is not None: # ping finished
            del p[ip] # remove from the process list
            if proc.returncode == 0:
                print('%s active' % ip)
            elif proc.returncode == 1:
                print('%s no response' % ip)
                print('%s error' % ip)

If you can run as a root you could use a pure Python ping script or scapy:

from scapy.all import sr, ICMP, IP, L3RawSocket, conf

conf.L3socket = L3RawSocket # for loopback interface
ans, unans = sr(IP(dst="")/ICMP(), verbose=0) # make requests
ans.summary(lambda (s,r): r.sprintf("%IP.src% is alive"))

System.BadImageFormatException An attempt was made to load a program with an incorrect format

For running it on any CPU either 62 bit or 32 bit follow these steps: Right click on the name of the project in Solution Explorer> Properties>Build and have these under Configuration: Active(Release), Platform:Active(Any CPU) and Target:x86. and just beside the Run button Select option Release and Any CPU from the options. And then Save it and Run.

"Operation must use an updateable query" error in MS Access

There is no error in the code, but the error is thrown due to the following:

 - Please check whether you have given Read-write permission to MS-Access database file.
 - The Database file where it is stored (say in Folder1) is read-only..? 

suppose you are stored the database (MS-Access file) in read only folder, while running your application the connection is not force-fully opened. Hence change the file permission / its containing folder permission like in C:\Program files all most all c drive files been set read-only so changing this permission solves this Problem.

Prevent WebView from displaying "web page not available"

We can set the visibility of webView to 0(view.INVISIBLE) and show some message. This code works for my app running on lolipop.

    public void onReceivedError(WebView webView, int errorCode, String description, String failingUrl) {
        // hide webView content and show custom msg
        Toast.makeText(NrumWebViewActivity.this,getString(R.string.server_not_responding), Toast.LENGTH_SHORT).show();

    public void onReceivedError(WebView view, WebResourceRequest req, WebResourceError rerr) {
        // Redirect to deprecated method, so you can use it in all SDK versions
        onReceivedError(view, rerr.getErrorCode(), rerr.getDescription().toString(), req.getUrl().toString());

How to browse localhost on Android device?

I use my local ip for that i.e. and it works.

Sort objects in ArrayList by date?

With introduction of Java 1.8, streams are very useful in solving this kind of problems:

Comparator <DateTime> myComparator = (arg1, arg2) 
                -> {
                       return -1;
                    else if (arg1.lteq(arg2))
                       return 0;
                       return 1;

ArrayList<DateTime> sortedList = myList

top -c command in linux to filter processes listed based on processname

I ended up using a shell script with the following code:


while [ 1 == 1 ]
    ps auxf |grep -ve "grep" |grep -E "MSG[^\ ]*" --color=auto
    sleep 5

Is there a way to continue broken scp (secure copy) command process in Linux?

If you need to resume an scp transfer from local to remote, try with rsync:

rsync --partial --progress --rsh=ssh local_file user@host:remote_file

Short version, as pointed out by @aurelijus-rozenas:

rsync -P -e ssh local_file user@host:remote_file

In general the order of args for rsync is

rsync [options] SRC DEST

Make a nav bar stick

add to your .nav css block the

position: fixed

and it will work

jQuery selector for the label of a checkbox

This should do it:


If you have non alphanumeric characters in your id then you must surround the attr value with quotes:


Slide div left/right using jQuery

The easiest way to do so is using jQuery and animate.css animation library.


/* --- Show DIV --- */
$( '.example' ).removeClass( 'fadeOutRight' ).show().addClass( 'fadeInRight' );

/* --- Hide DIV --- */
$( '.example' ).removeClass( 'fadeInRight' ).addClass( 'fadeOutRight' );


<div class="example">Some text over here.</div>

Easy enough to implement. Just don't forget to include the animate.css file in the header :)

Refresh certain row of UITableView based on Int in Swift


    func reloadYourRows(name: <anyname>) {
    let row = <your array name>.index(of: <name passing in>)
    let reloadPath = IndexPath(row: row!, section: 0)
    tableView.reloadRows(at: [reloadPath], with: .middle)

Visual studio code terminal, how to run a command with administrator rights?

Running as admin didn't help me. (also got errors with syscall: rename)

Turns out this error can also occur if files are locked by Windows.

This can occur if :

  • You are actually running the project
  • You have files open in both Visual Studio and VSCode.

Running as admin doesn't get around windows file locking.

I created a new project in VS2017 and then switched to VSCode to try to add more packages. After stopping the project from running and closing VS2017 it was able to complete without error

Disclaimer: I'm not exactly sure if this means running as admin isn't necessary, but try to avoid it if possible to avoid the possibility of some rogue package doing stuff it isn't meant to.

Why do I get "MismatchSenderId" from GCM server side?

I encountered the same issue recently and I tried different values for "gcm_sender_id" based on the project ID. However, the "gcm_sender_id" value must be set to the "Project Number".

You can find this value under: Menu > IAM & Admin > Settings.

See screenshot: GCM Project Number

How to set the locale inside a Debian/Ubuntu Docker container?

Rather than resetting the locale after the installation of the locales package you can answer the questions you would normally get asked (which is disabled by noninteractive) before installing the package so that the package scripts setup the locale correctly, this example sets the locale to english (British, UTF-8):

RUN echo locales locales/default_environment_locale select en_GB.UTF-8 | debconf-set-selections
RUN echo locales locales/locales_to_be_generated select "en_GB.UTF-8 UTF-8" | debconf-set-selections

  apt-get update && \
  DEBIAN_FRONTEND=noninteractive apt-get install -y locales && \
  rm -rf /var/lib/apt/lists/*

How do I get the max ID with Linq to Entity?

Do that like this

db.Users.OrderByDescending(u => u.UserId).FirstOrDefault();

Making a WinForms TextBox behave like your browser's address bar

This worked for a WPF/XAML TextBox.

    private bool initialEntry = true;
    private void TextBox_SelectionChanged(object sender, RoutedEventArgs e)
        if (initialEntry)
            e.Handled = true;
            initialEntry = false;
    private void TextBox_GotFocus(object sender, RoutedEventArgs e)
        initialEntry = true;      

How to make <div> fill <td> height

Really have to do this with JS. Here's a solution. I didn't use your class names, but I called the div within the td class name of "full-height" :-) Used jQuery, obviously. Note this was called from jQuery(document).ready(function(){ setFullHeights();}); Also note if you have images, you are going to have to iterate through them first with something like:

function loadedFullHeights(){
var imgCount = jQuery(".full-height").find("img").length;
    return setFullHeights();
var loaded = 0;
    if(loaded ===imgCount){


And you would want to call the loadedFullHeights() from docReady instead. This is actually what I ended up using just in case. Got to think ahead you know!

function setFullHeights(){
var par;
var height;
var $ = jQuery;
var heights=[];
var i = 0;
    par =$(this).parent();
    height = $(par).height();
    var tPad = Number($(par).css('padding-top').replace('px',''));
    var bPad = Number($(par).css('padding-bottom').replace('px',''));
    height -= tPad+bPad;
for(ii in heights){
    $(".full-height").eq(ii).css('height', heights[ii]+'px');


How to insert a new line in Linux shell script?

Use this echo statement

 echo -e "Hai\nHello\nTesting\n"

The output is



<table border="1"></table>

should do the trick.

How do I create a file at a specific path?

f = open("", "a") Will be created in whatever directory the python file is run from.

I'm not sure about the other error...I don't work in windows.

Ping all addresses in network, windows

An expansion and useful addition to egmackenzie's "arp -a" solution for Windows -

Windows Example searching for my iPhone on the WiFi network

(pre: iPhone WiFi disabled)

  • Open Command Prompt in Admin mode (R.C. Start & look in menu)
  • arp -d <- clear the arp listing!
  • ping <- take your subnet, and ping '255', everyone
  • arp -a
  • iPhone WiFi on
  • ping
  • arp -a

See below for example:

enter image description here

Here is a nice writeup on the use of 'arp -d' here if interested -

How to synchronize or lock upon variables in Java?

If on another occasion you're synchronising a Collection rather than a String, perhaps you're be iterating over the collection and are worried about it mutating, Java 5 offers:

How to use Apple's new San Francisco font on a webpage

Apple is abstracting the system fonts going forward. This facility uses new generic family name -apple-system. So something like below should get you what you want.

  font-family: -apple-system, "Helvetica Neue", "Lucida Grande";


I had similar problem when I tried to build a signed apk for my app.

Strange, it happened only when I wanted to build a release apk, while on debug apk everything worked OK.

Finally, looking on this thread, I checked for support library duplications in build.gradle and removed any duplications but this wasn't enough..

I had to do clean project and only then finally I've got it to work.

Oracle Convert Seconds to Hours:Minutes:Seconds

create or replace function `seconds_hh_mi_ss` (seconds in number)     
return varchar2
hours_var number;    
minutes_var number;    
seconds_var number;    
remeinder_var number;    
output_var varchar2(32);    
select seconds - mod(seconds,3600) into hours_var from dual;    
select seconds - hours_var into remeinder_var from dual;    
select (remeinder_var - mod(remeinder_var,60)) into minutes_var from dual;    
select seconds - (hours_var+minutes_var) into seconds_var from dual;    
output_var := hours_var/3600||':'||minutes_var/60||':'||seconds_var;    

How do I find if a string starts with another string in Ruby?

puts 'abcdefg'.start_with?('abc')  #=> true

[edit] This is something I didn't know before this question: start_with takes multiple arguments.

'abcdefg'.start_with?( 'xyz', 'opq', 'ab')

How to get Domain name from URL using jquery..?

You can use a trick, by creating a <a>-element, then setting the string to the href of that <a>-element and then you have a Location object you can get the hostname from.

You could either add a method to the String prototype:

String.prototype.toLocation = function() {
    var a = document.createElement('a');
    a.href = this;
    return a;

and use it like this:

or make it a function:

function toLocation(url) {
    var a = document.createElement('a');
    a.href = url;
    return a;

and use it like this:

both of these will output: ""

If you also need the protocol, you can do something like this:

var url = "".toLocation();
url.protocol + "//" + url.hostname

which will output: ""

List columns with indexes in PostgreSQL

Just do: \d table_name

But I'm not sure what do you mean that the information about columns is not there.

For example:

# \d pg_class
       Table "pg_catalog.pg_class"
     Column      |   Type    | Modifiers
 relname         | name      | not null
 relnamespace    | oid       | not null
 reltype         | oid       | not null
 reloftype       | oid       | not null
 relowner        | oid       | not null
 relam           | oid       | not null
 relfilenode     | oid       | not null
 reltablespace   | oid       | not null
 relpages        | integer   | not null
 reltuples       | real      | not null
 reltoastrelid   | oid       | not null
 reltoastidxid   | oid       | not null
 relhasindex     | boolean   | not null
 relisshared     | boolean   | not null
 relistemp       | boolean   | not null
 relkind         | "char"    | not null
 relnatts        | smallint  | not null
 relchecks       | smallint  | not null
 relhasoids      | boolean   | not null
 relhaspkey      | boolean   | not null
 relhasexclusion | boolean   | not null
 relhasrules     | boolean   | not null
 relhastriggers  | boolean   | not null
 relhassubclass  | boolean   | not null
 relfrozenxid    | xid       | not null
 relacl          | aclitem[] |
 reloptions      | text[]    |
    "pg_class_oid_index" UNIQUE, btree (oid)
    "pg_class_relname_nsp_index" UNIQUE, btree (relname, relnamespace)

It clearly shows which columns given index is on this table.

What are the differences between using the terminal on a mac vs linux?

If you did a new or clean install of OS X version 10.3 or more recent, the default user terminal shell is bash.

Bash is essentially an enhanced and GNU freeware version of the original Bourne shell, sh. If you have previous experience with bash (often the default on GNU/Linux installations), this makes the OS X command-line experience familiar, otherwise consider switching your shell either to tcsh or to zsh, as some find these more user-friendly.

If you upgraded from or use OS X version 10.2.x, 10.1.x or 10.0.x, the default user shell is tcsh, an enhanced version of csh('c-shell'). Early implementations were a bit buggy and the programming syntax a bit weird so it developed a bad rap.

There are still some fundamental differences between mac and linux as Gordon Davisson so aptly lists, for example no useradd on Mac and ifconfig works differently.

The following table is useful for knowing the various unix shells.

sh      The original Bourne shell   Present on every unix system 
ksh     Original Korn shell         Richer shell programming environment than sh 
csh     Original C-shell            C-like syntax; early versions buggy 
tcsh    Enhanced C-shell            User-friendly and less buggy csh implementation 
bash    GNU Bourne-again shell      Enhanced and free sh implementation 
zsh     Z shell                     Enhanced, user-friendly ksh-like shell

You may also find these guides helpful:

On a final note, I am on Linux (Ubuntu 11) and Mac osX so I use bash and the thing I like the most is customizing the .bashrc (source'd from .bash_profile on OSX) file with aliases, some examples below. I now placed all my aliases in a separate .bash_aliases file and include it with:

if [ -f ~/.bash_aliases ]; then
    . ~/.bash_aliases

in the .bashrc or .bash_profile file.

Note that this is an example of a mac-linux difference because on a Mac you can't have the --color=auto. The first time I did this (without knowing) I redefined ls to be invalid which was a bit alarming until I removed --auto-color !

You may also find useful

# ~/.bash_aliases
# ls variants
#alias l='ls -CF' 
alias la='ls -A' 
alias l='ls -alFtr' 
alias lsd='ls -d .*' 
# Various
alias h='history | tail'
alias hg='history | grep'
alias mv='mv -i' 
alias zap='rm -i'
# One letter quickies:
alias p='pwd'
alias x='exit'
alias {ack,ak}='ack-grep'
# Directories
alias s='cd ..'
alias play='cd ~/play/'
# Rails
alias src='script/rails console'
alias srs='script/rails server'
alias raked='rake db:drop db:create db:migrate db:seed' 
alias rvm-restart='source '\''/home/durrantm/.rvm/scripts/rvm'\'''
alias rrg='rake routes | grep '
alias rspecd='rspec --drb '
# DropBox - syncd
alias work="cd $WORKBASE"
alias code="cd $WORKBASE/ror/code"
# DropNot - NOT syncd !
alias {dropnot,not}="cd $WORKBASE_GIT"
alias {webs,ww}="cd $WORKBASE_GIT/webs"
alias {setups,docs}="cd $WORKBASE_GIT/setups_and_docs"
alias {linker,lnk}="cd $WORKBASE_GIT/webs/rails_v3/linker"
# git
alias {gsta,gst}='git status' 
# Warning: gst conflicts with gnu-smalltalk (when used).
alias {gbra,gb}='git branch'
alias {gco,go}='git checkout'
alias {gcob,gob}='git checkout -b '
alias {gadd,ga}='git add '
alias {gcom,gc}='git commit'
alias {gpul,gl}='git pull '
alias {gpus,gh}='git push '
alias glom='git pull origin master'
alias ghom='git push origin master'
alias gg='git grep '
# vim
alias v='vim'
# tmux
alias {ton,tn}='tmux set -g mode-mouse on'
alias {tof,tf}='tmux set -g mode-mouse off'
# dmc
alias {dmc,dm}='cd ~/Dropnot/webs/rails_v3/dmc/'
alias wf='cd ~/Dropnot/webs/rails_v3/dmc/dmWorkflow'
alias ws='cd ~/Dropnot/webs/rails_v3/dmc/dmStaffing'

Looping through the content of a file in Bash

This is coming rather very late, but with the thought that it may help someone, i am adding the answer. Also this may not be the best way. head command can be used with -n argument to read n lines from start of file and likewise tail command can be used to read from bottom. Now, to fetch nth line from file, we head n lines, pipe the data to tail only 1 line from the piped data.

   TOTAL_LINES=`wc -l $USER_FILE | cut -d " " -f1 `
   echo $TOTAL_LINES       # To validate total lines in the file

   for (( i=1 ; i <= $TOTAL_LINES; i++ ))
      LINE=`head -n$i $USER_FILE | tail -n1`
      echo $LINE

How to save LogCat contents to file?

Open command prompt and locate your adb.exe(it will be in your android-sdk/platform-tools)

adb logcat -d > <path-where-you-want-to-save-file>/filename.txt

If you omit path, it will save logcat in current working directory

The -d option indicates that you are dumping the current contents and then exiting. Prefer notepad++ to open this file so that you can get everything in a proper readable format.

Is try-catch like error handling possible in ASP Classic?

Been a while since I was in ASP land, but iirc there's a couple of ways:

try catch finally can be reasonably simulated in VBS (good article here here) and there's an event called class_terminate you can watch and catch exceptions globally in. Then there's the possibility of changing your scripting language...

Sending HTML Code Through JSON

Just to expand on @T.J. Crowder's answer.

json_encode does well with simple html strings, in my experience however json_encode often becomes confused by, (or it becomes quite difficult to properly escape) longer complex nested html mixed with php. Two options to consider if you are in this position are: encoding/decoding the markup first with something like [base64_encode][1]/ decode (quite a bit of a performance hit), or (and perhaps preferably) be more selective in what you are passing via json, and generate the necessary markup on the client side instead.

Most recent previous business day in Python

Why don't you try something like:

lastBusDay =
if not in range(0,5):
    lastBusDay = 5

gridview data export to excel in

I don't there there is any DataSource for the gridview
Though you have DataBind in your code as


Nested ifelse statement

Using the SQL CASE statement with the dplyr and sqldf packages:


df <-structure(list(idnat = structure(c(2L, 2L, 2L, 1L), .Label = c("foreign", 
"french"), class = "factor"), idbp = structure(c(3L, 1L, 4L, 
2L), .Label = c("colony", "foreign", "mainland", "overseas"), class = "factor")), .Names = c("idnat", 
"idbp"), class = "data.frame", row.names = c(NA, -4L))


sqldf("SELECT idnat, idbp,
          WHEN idbp IN ('colony', 'overseas') THEN 'overseas' 
          ELSE idbp 
        END AS idnat2
       FROM df")


df %>% 
mutate(idnat2 = case_when(.$idbp == 'mainland' ~ "mainland", 
                          .$idbp %in% c("colony", "overseas") ~ "overseas", 
                         TRUE ~ "foreign"))


    idnat     idbp   idnat2
1  french mainland mainland
2  french   colony overseas
3  french overseas overseas
4 foreign  foreign  foreign

Disabling Controls in Bootstrap

also you can use "readonly"

<select id="xxx" name="xxx" class="input-medium" readonly>

Set textarea width to 100% in bootstrap modal

I am new to .NET/MVC programming, but my understanding is that the Site.css file (under the Content folder in MVC) is a site-level override for Bootstrap CSS, allowing you to override bootstrap native settings in a portable and non-destructive manner (e.g. you can easily save and reapply your site.css changes when updating Bootstrap on your system.)

In Bootstrap 3.0.0, Site.css has the following style setting:

/* Set width on the form input elements since they're 100% wide by default */
textarea {
    max-width: 280px;

Other blogs have suggested that this 280px width was added in haste near a release date, in a desire to make the UI look better than it does with 100% width input. Fortunately it was placed in a "visible" location in the site file so you would notice it.

Simply change the width setting, either for all three input types, or pull out textarea and give it its own setting if you want to leave the others alone.

How to return 2 values from a Java method?

You don't need to create your own class to return two different values. Just use a HashMap like this:

private HashMap<Toy, GameLevel> getToyAndLevelOfSpatial(Spatial spatial)
    Toy toyWithSpatial = firstValue;
    GameLevel levelToyFound = secondValue;

    HashMap<Toy,GameLevel> hm=new HashMap<>();
    hm.put(toyWithSpatial, levelToyFound);
    return hm;

private void findStuff()
    HashMap<Toy, GameLevel> hm = getToyAndLevelOfSpatial(spatial);
    Toy firstValue = hm.keySet().iterator().next();
    GameLevel secondValue = hm.get(firstValue);

You even have the benefit of type safety.

What is the best way to clone/deep copy a .NET generic Dictionary<string, T>?

You could always use serialization. You could serialize the object then deserialize it. That will give you a deep copy of the Dictionary and all the items inside of it. Now you can create a deep copy of any object that is marked as [Serializable] without writing any special code.

Here are two methods that will use Binary Serialization. If you use these methods you simply call

object deepcopy = FromBinary(ToBinary(yourDictionary));

public Byte[] ToBinary()
  MemoryStream ms = null;
  Byte[] byteArray = null;
    BinaryFormatter serializer = new BinaryFormatter();
    ms = new MemoryStream();
    serializer.Serialize(ms, this);
    byteArray = ms.ToArray();
  catch (Exception unexpected)
    if (ms != null)
  return byteArray;

public object FromBinary(Byte[] buffer)
  MemoryStream ms = null;
  object deserializedObject = null;

    BinaryFormatter serializer = new BinaryFormatter();
    ms = new MemoryStream();
    ms.Write(buffer, 0, buffer.Length);
    ms.Position = 0;
    deserializedObject = serializer.Deserialize(ms);
    if (ms != null)
  return deserializedObject;

Constructor overloading in Java - best practice

I think the best practice is to have single primary constructor to which the overloaded constructors refer to by calling this() with the relevant parameter defaults. The reason for this is that it makes it much clearer what is the constructed state of the object is - really you can think of the primary constructor as the only real constructor, the others just delegate to it

One example of this might be JTable - the primary constructor takes a TableModel (plus column and selection models) and the other constructors call this primary constructor.

For subclasses where the superclass already has overloaded constructors, I would tend to assume that it is reasonable to treat any of the parent class's constructors as primary and think it is perfectly legitimate not to have a single primary constructor. For example,when extending Exception, I often provide 3 constructors, one taking just a String message, one taking a Throwable cause and the other taking both. Each of these constructors calls super directly.

An established connection was aborted by the software in your host machine

This problem may also occur when you are opening Android Studio and Eclipse at once. Try to close one of them and it might solve your issue.

Uninstall Django completely

On Windows, I had this issue with static files cropping up under pydev/eclipse with python 2.7, due to an instance of django (1.8.7) that had been installed under cygwin. This caused a conflict between windows style paths and cygwin style paths. So, unfindable static files despite all the above fixes. I removed the extra distribution (so that all packages were installed by pip under windows) and this fixed the issue.

What is the pythonic way to detect the last element in a 'for' loop?

if the items are unique:

for x in list:
    if x == list[-1]:

other options:

pos = -1
for x in list:
    pos += 1
    if pos == len(list) - 1:

for x in list:
#code - e.g. print x

if len(list) > 0:
    for x in list[:-1]
    for x in list[-1]:

Split value from one field to two

This takes smhg from here and curt's from Last index of a given substring in MySQL and combines them. This is for mysql, all I needed was to get a decent split of name to first_name last_name with the last name a single word, the first name everything before that single word, where the name could be null, 1 word, 2 words, or more than 2 words. Ie: Null; Mary; Mary Smith; Mary A. Smith; Mary Sue Ellen Smith;

So if name is one word or null, last_name is null. If name is > 1 word, last_name is last word, and first_name all words before last word.

Note that I've already trimmed off stuff like Joe Smith Jr. ; Joe Smith Esq. and so on, manually, which was painful, of course, but it was small enough to do that, so you want to make sure to really look at the data in the name field before deciding which method to use.

Note that this also trims the outcome, so you don't end up with spaces in front of or after the names.

I'm just posting this for others who might google their way here looking for what I needed. This works, of course, test it with the select first.

It's a one time thing, so I don't care about efficiency.

        LOCATE(' ', `name`) > 0,
        LEFT(`name`, LENGTH(`name`) - LOCATE(' ', REVERSE(`name`))),
) AS first_name,
        LOCATE(' ', `name`) > 0,
        SUBSTRING_INDEX(`name`, ' ', -1) ,
) AS last_name
FROM `users`;

UPDATE `users` SET
`first_name` = TRIM( 
        LOCATE(' ', `name`) > 0,
        LEFT(`name`, LENGTH(`name`) - LOCATE(' ', REVERSE(`name`))),
`last_name` = TRIM( 
        LOCATE(' ', `name`) > 0,
        SUBSTRING_INDEX(`name`, ' ', -1) ,

Is it possible to return empty in react render function?

for those developers who came to this question about checking where they can return null from component instead of checking in ternary mode to render or not render the component, the answer is YES, You Can!

i mean instead of this junk ternary condition inside your jsx in render part of your component:

// some component body
   {/* some ui */}
   { someCondition && <MyComponent /> }
   { someCondition ? <MyComponent /> : null }

   {/* more ui */}

you can check than condition inside your component like:

const MyComponent:React.FC = () => {
  // get someCondition from context at here before any thing

  if(someCondition) return null; // i mean this part , checking inside component! 
  return (
     // some ui...

Just Consider that in my case i provide the someCondition variable from a context in upper level component ( for example, just consider in your mind ) and i don't need to prop drill the someCondition inside MyComponent.

Just look how clean view your code gets after that, i mean you don't need to user ternary operator inside your JSX, and your parent component would like below:

// some component body
   {/* some ui */}
   <MyComponent />

   {/* more ui */}

and MyComponent would handle the rest for you!

Get filename in batch for loop

The answer by @AKX works on the command line, but not within a batch file. Within a batch file, you need an extra %, like this:

@echo off
for /R TutorialSteps %%F in (*.py) do echo %%~nF

SQL query for finding records where count > 1

Try this query:

SELECT column_name
  FROM table_name
 GROUP BY column_name
HAVING COUNT(column_name) = 1;

SQL Inner join 2 tables with multiple column conditions and update

You need to do

Update table_xpto
set column_xpto = x.xpto_New
    ,column2 = x.column2New
from table_xpto xpto
   inner join table_xptoNew xptoNew ON xpto.bla = xptoNew.Bla
where <clause where>

If you need a better answer, you can give us more information :)

Highlight a word with jQuery

I have created a repository on similar concept that changes the colors of the texts whose colors are recognised by html5 (we don't have to use actual #rrggbb values and could just use the names as html5 standardised about 140 of them)

colors.js colors.js

$( document ).ready(function() {_x000D_
 function hiliter(word, element) {_x000D_
  var rgxp = new RegExp("\\b" + word + "\\b" , 'gi'); // g modifier for global and i for case insensitive _x000D_
  var repl = '<span class="myClass">' + word + '</span>';_x000D_
  element.innerHTML = element.innerHTML.replace(rgxp, repl);_x000D_
 hiliter('dolor', document.getElementById('dolor'));_x000D_
<!DOCTYPE html>_x000D_
  <script src=""></script>_x000D_
   <link href="main.css" type="text/css"  rel="stylesheet"/>_x000D_
 <body id='dolor'>_x000D_
<p >_x000D_
    Lorem ipsum dolor sit amet, consectetuer adipiscing elit._x000D_
    Quisque bibendum sem ut lacus. Integer dolor ullamcorper libero._x000D_
    Aliquam rhoncus eros at augue. Suspendisse vitae mauris._x000D_
 <script type="text/javascript" src="main.js" charset="utf-8"></script>_x000D_

Floating point exception( core dump

Floating Point Exception happens because of an unexpected infinity or NaN. You can track that using gdb, which allows you to see what is going on inside your C program while it runs. For more details:

In a nutshell, these commands might be useful...

gcc -g myprog.c

gdb a.out

gdb core a.out

ddd a.out

Could not establish secure channel for SSL/TLS with authority '*'

Here is what fixed for me:

1) Make sure you are running Visual Studio as Administrator

2) Install and run winhttpcertcfg.exe to grant access

The command is similar to below: (enter your certificate subject and service name)

winhttpcertcfg -g -c LOCAL_MACHINE\MY -s "certificate subject" -a "NetworkService"
winhttpcertcfg -g -c LOCAL_MACHINE\MY -s "certificate subject" -a "LOCAL SERVICE"
winhttpcertcfg -g -c LOCAL_MACHINE\MY -s "certificate subject" -a "My Apps Service Account"

Why are #ifndef and #define used in C++ header files?

#ifndef <token>
/* code */
/* code to include if the token is defined */

#ifndef checks whether the given token has been #defined earlier in the file or in an included file; if not, it includes the code between it and the closing #else or, if no #else is present, #endif statement. #ifndef is often used to make header files idempotent by defining a token once the file has been included and checking that the token was not set at the top of that file.

#ifndef _INCL_GUARD
#define _INCL_GUARD

Android disable screen timeout while app is running

In a View, in my case a SurfaceView subclass, you can set the screen on always on. I wanted the screen to stay on while this view was still drawing stuff.

public class MyCoolSurfaceView extends SurfaceView { 
protected void onAttachedToWindow (){

protected void onDetachedFromWindow(){

Putting GridView data in a DataTable

protected void btnExportExcel_Click(object sender, EventArgs e)
    DataTable _datatable = new DataTable();
    for (int i = 0; i < grdReport.Columns.Count; i++)
    foreach (GridViewRow row in grdReport.Rows)
        DataRow dr = _datatable.NewRow();
        for (int j = 0; j < grdReport.Columns.Count; j++)
            if (!row.Cells[j].Text.Equals("&nbsp;"))
                dr[grdReport.Columns[j].ToString()] = row.Cells[j].Text;


Node.js Best Practice Exception Handling

You can catch uncaught exceptions, but it's of limited use. See

monit, forever or upstart can be used to restart node process when it crashes. A graceful shutdown is best you can hope for (e.g. save all in-memory data in uncaught exception handler).

How to validate inputs dynamically created using ng-repeat, ng-show (angular)

Since the question was asked the Angular team has solved this issue by making it possible to dynamically create input names.

With Angular version 1.3 and later you can now do this:

<form name="vm.myForm" novalidate>
  <div ng-repeat="p in vm.persons">
    <input type="text" name="person_{{$index}}" ng-model="p" required>
    <span ng-show="vm.myForm['person_' + $index].$invalid">Enter a name</span>


Angular 1.3 also introduced ngMessages, a more powerful tool for form validation. You can use the same technique with ngMessages:

<form name="vm.myFormNgMsg" novalidate>
    <div ng-repeat="p in vm.persons">
      <input type="text" name="person_{{$index}}" ng-model="p" required>
      <span ng-messages="vm.myFormNgMsg['person_' + $index].$error">
        <span ng-message="required">Enter a name</span>

How can I make Java print quotes, like "Hello"?

Adding the actual quote characters is only a tiny fraction of the problem; once you have done that, you are likely to face the real problem: what happens if the string already contains quotes, or line feeds, or other unprintable characters?

The following method will take care of everything:

public static String escapeForJava( String value, boolean quote )
    StringBuilder builder = new StringBuilder();
    if( quote )
        builder.append( "\"" );
    for( char c : value.toCharArray() )
        if( c == '\'' )
            builder.append( "\\'" );
        else if ( c == '\"' )
            builder.append( "\\\"" );
        else if( c == '\r' )
            builder.append( "\\r" );
        else if( c == '\n' )
            builder.append( "\\n" );
        else if( c == '\t' )
            builder.append( "\\t" );
        else if( c < 32 || c >= 127 )
            builder.append( String.format( "\\u%04x", (int)c ) );
            builder.append( c );
    if( quote )
        builder.append( "\"" );
    return builder.toString();

How does one sum only those rows in excel not filtered out?

If you aren't using an auto-filter (i.e. you have manually hidden rows), you will need to use the AGGREGATE function instead of SUBTOTAL.

Disabling Warnings generated via _CRT_SECURE_NO_DEPRECATE

For the warning by warning case, It's wise to restore it to default at some point, since you are doing it on a case by case basis.

#pragma warning(disable: 4996) /* Disable deprecation */
// Code that causes it goes here
#pragma warning(default: 4996) /* Restore default */

Can Windows' built-in ZIP compression be scripted?

Here'a my attempt to summarize built-in capabilities windows for compression and uncompression - How can I compress (/ zip ) and uncompress (/ unzip ) files and folders with batch file without using any external tools?

with a few given solutions that should work on almost every windows machine.

As regards to the shell.application and WSH I preferred the jscript as it allows a hybrid batch/jscript file (with .bat extension) that not require temp files.I've put unzip and zip capabilities in one file plus a few more features.

What does android:layout_weight mean?

For additional:

For vertical orientation, don't forget set height to 0dp


For horizontal orientation, don't forget set width to 0dp


Maven fails to find local artifact

As the options here didn't work for me, I'm sharing how I solved it:

My project has a parent project (with its own pom.xml) that has many children modules, one of which (A) has a dependency to another child (B). When I tried mvn package in A, it didn't work because B could not be resolved.

Executing mvn install in the parent directory did the job. After that, I could do mvn package inside of A and only then it could find B.

Changing file extension in Python

Use this:


And here is how the above works:

The splitext method separates the name from the extension creating a tuple:


the created tuple now contains the strings "name" and "fasta". Then you need to access only the string "name" which is the first element of the tuple:


And then you want to add a new extension to that name:


How to find a string inside a entire database?

Here are couple more free tools that can be used for this. Both work as SSMS addins.

ApexSQL Search – 100% free - searches both schema and data in tables. Has couple more useful options such as dependency tracking…

SSMS Tools pack – free for all versions except SQL 2012 – doesn’t look as advanced as previous one but has a lot of other cool features.

How to convert hex strings to byte values in Java

Here, if you are converting string into byte[].There is a utility code :

    String[] str = result.replaceAll("\\[", "").replaceAll("\\]","").split(", ");
    byte[] dataCopy = new byte[str.length] ;
    int i=0;
    for(String s:str ) {
    return dataCopy;

What is Linux’s native GUI API?

Strictly speaking, the API of Linux consists of its system calls. These are all of the kernel functions that can be called by a user-mode (non-kernel) program. This is a very low-level interface that allows programs to do things like open and read files. See for a general introduction.

A real Linux system will also have an entire "stack" of other software running on it, in order to provide a graphical user interface and other features. Each element of this stack will offer its own API.

How to Set OnClick attribute with value containing function in ie8?

your best bet is to use a javascript framework like jquery or prototype, but, failing that, you should use:

if (foo.addEventListener) 
    foo.addEventListener('click',doit,false); //everything else    
else if (foo.attachEvent)
    foo.attachEvent('onclick',doit);  //IE only


also, your function is a little off. it should be

var doit = function(){
    alert('hello world!');

What's the difference between ClusterIP, NodePort and LoadBalancer service types in Kubernetes?

To clarify for anyone who is looking for what is the difference between the 3 on a simpler level. You can expose your service with minimal ClusterIp (within k8s cluster) or larger exposure with NodePort (within cluster external to k8s cluster) or LoadBalancer (external world or whatever you defined in your LB).

ClusterIp exposure < NodePort exposure < LoadBalancer exposure

  • ClusterIp
    Expose service through k8s cluster with ip/name:port
  • NodePort
    Expose service through Internal network VM's also external to k8s ip/name:port
  • LoadBalancer
    Expose service through External world or whatever you defined in your LB.

jQuery Validate Plugin - How to create a simple custom rule?

    var response;
        function(value, element) {
                type: "POST",
                url: "http://""/checkUser.php",
                data: "checkUsername="+value,
                success: function(msg)
                    //If username exists, set response to true
                    response = ( msg == 'true' ) ? true : false;
            return response;
        "Username is Already Taken"

        username: {
            required: true,
            minlength: 8,
            uniqueUserName: true
        messages: {
            username: {
                required: "Username is required",
                minlength: "Username must be at least 8 characters",
                uniqueUserName: "This Username is taken already"

JavaScript moving element in the DOM

Trivial with jQuery


If you want to do it repeatedly, you'll need to use different selectors since the divs will retain their ids as they are moved around.

$(function() {
    setInterval( function() {
    }, 3000 );

Javascript how to split newline

  1. Move the var ks = $('#keywords').val().split("\n"); inside the event handler
  2. Use alert(ks[k]) instead of alert(k)

           var ks = $('#keywords').val().split("\n");
           $.each(ks, function(k){


What is the C++ function to raise a number to a power?

Many answers have suggested pow() or similar alternatives or their own implementations. However, given the examples (2^1, 2^2 and 2^3) in your question, I would guess whether you only need to raise 2 to an integer power. If this is the case, I would suggest you to use 1 << n for 2^n.

What is the difference between UNION and UNION ALL?

Important! Difference between Oracle and Mysql: Let's say that t1 t2 don't have duplicate rows between them but they have duplicate rows individual. Example: t1 has sales from 2017 and t2 from 2018




In ORACLE UNION ALL fetches all rows from both tables. The same will occur in MySQL.





In ORACLE, UNION fetches all rows from both tables because there are no duplicate values between t1 and t2. On the other hand in MySQL the resultset will have fewer rows because there will be duplicate rows within table t1 and also within table t2!

How to Upload Image file in Retrofit 2

Retrofit 2.0 solution

public Call<CommonResponse> requestUpdateImage(@PartMap Map<String, RequestBody> map);


    Map<String, RequestBody> params = new HashMap<>();

    params.put("newProfilePicture" + "\"; filename=\"" + FilenameUtils.getName(file.getAbsolutePath()), RequestBody.create(MediaType.parse("image/jpg"), file));

 Call<CommonResponse> call = request.requestUpdateImage(params);

you can use
image/jpg image/png image/gif

Why call super() in a constructor?

There is an implicit call to super() with no arguments for all classes that have a parent - which is every user defined class in Java - so calling it explicitly is usually not required. However, you may use the call to super() with arguments if the parent's constructor takes parameters, and you wish to specify them. Moreover, if the parent's constructor takes parameters, and it has no default parameter-less constructor, you will need to call super() with argument(s).

An example, where the explicit call to super() gives you some extra control over the title of the frame:

class MyFrame extends JFrame
    public MyFrame() {
        super("My Window Title");

Html ordered list 1.1, 1.2 (Nested counters and scope) not working

Keep it Simple!

Simpler and a Standard solution to increment the number and to retain the dot at the end. Even if you get the css right, it will not work if your HTML is not correct. see below.


ol {
  counter-reset: item;
ol li {
  display: block;
ol li:before {
  content: counters(item, ". ") ". ";
  counter-increment: item;


ol {
    counter-reset: item;
    li {
        display: block;
        &:before {
            content: counters(item, ". ") ". ";
            counter-increment: item

HTML Parent Child

If you add the child make sure the it is under the parent li.

<!-- WRONG -->
    <li>Parent 1</li> <!-- Parent is Individual. Not hugging -->
    <li>Parent 2</li>

<!-- RIGHT -->
    <li>Parent 1 
    </li> <!-- Parent is Hugging the child -->
    <li>Parent 2</li>

How do I import a .dmp file into Oracle?

.dmp files are dumps of oracle databases created with the "exp" command. You can import them using the "imp" command.

If you have an oracle client intalled on your machine, you can executed the command

imp help=y

to find out how it works. What will definitely help is knowing from wich schema the data was exported and what the oracle version was.

How to use OKHTTP to make a post request?

OkHttp POST request with token in header

       RequestBody requestBody = new MultipartBody.Builder()
            .addFormDataPart("search", "a")
            .addFormDataPart("model", "1")
            .addFormDataPart("in", "1")
            .addFormDataPart("id", "1")
    OkHttpClient client = new OkHttpClient();
    okhttp3.Request request = new okhttp3.Request.Builder()
            .addHeader("token", "eyJ0eXAiOiJKV1QiLCJhbGciOiJIUzI1NiJ9.eyJpc3MiOiIkMnkkMTAkZzZrLkwySlFCZlBmN1RTb3g3bmNpTzltcVwvemRVN2JtVC42SXN0SFZtbzZHNlFNSkZRWWRlIiwic3ViIjo0NSwiaWF0IjoxNTUwODk4NDc0LCJleHAiOjE1NTM0OTA0NzR9.tefIaPzefLftE7q0yKI8O87XXATwowEUk_XkAOOQzfw")
            .addHeader("cache-control", "no-cache")
            .addHeader("Postman-Token", "7e231ef9-5236-40d1-a28f-e5986f936877")

    client.newCall(request).enqueue(new Callback() {
        public void onFailure(Call call, IOException e) {

        public void onResponse(Call call, okhttp3.Response response) throws IOException {
            if (response.isSuccessful()) {
                final String myResponse = response.body().string();

                MainActivity.this.runOnUiThread(new Runnable() {
                    public void run() {
                        Log.d("response", myResponse);

Regex for string contains?

Assuming regular PCRE-style regex flavors:

If you want to check for it as a single, full word, it's \bTest\b, with appropriate flags for case insensitivity if desired and delimiters for your programming language. \b represents a "word boundary", that is, a point between characters where a word can be considered to start or end. For example, since spaces are used to separate words, there will be a word boundary on either side of a space.

If you want to check for it as part of the word, it's just Test, again with appropriate flags for case insensitivity. Note that usually, dedicated "substring" methods tend to be faster in this case, because it removes the overhead of parsing the regex.

use Lodash to sort array of object by value

You can use lodash sortBy (

Your code could be like:

const myArray = [  
      "name":"Anakin Skywalker",
      "name":"Luke Skywalker",

const myOrderedArray = _.sortBy(myArray, o =>

UIImage resize (Scale proportion)

I used this single line of code to create a new UIImage which is scaled. Set the scale and orientation params to achieve what you want. The first line of code just grabs the image.

    // grab the original image
    UIImage *originalImage = [UIImage imageNamed:@"myImage.png"];
    // scaling set to 2.0 makes the image 1/2 the size. 
    UIImage *scaledImage = 
                [UIImage imageWithCGImage:[originalImage CGImage] 
                              scale:(originalImage.scale * 2.0)

Convert YYYYMMDD string date to a datetime value

You should have to use DateTime.TryParseExact.

var newDate = DateTime.ParseExact("20111120", 


string str = "20111021";
string[] format = {"yyyyMMdd"};
DateTime date;

if (DateTime.TryParseExact(str, 
                           out date))

DataTables: Uncaught TypeError: Cannot read property 'defaults' of undefined

I got the same error, I'm using laravel 5.4 with webpack, here package.json before:

  "devDependencies": {
    "jquery": "^1.12.4",
  "dependencies": {
    "": "^2.1.1",

I had to move jquery and npm packages under one of these "dependencies": {} or "devDependencies": {} in package.json and the error disappeared, after:

  "devDependencies": {
    "jquery": "^1.12.4",
    "": "^2.1.1",

I hope that helps!

Passing a string with spaces as a function argument in bash

Your definition of myFunction is wrong. It should be:

    # same as before


function myFunction
    # same as before

Anyway, it looks fine and works fine for me on Bash 3.2.48.

Python datetime strptime() and strftime(): how to preserve the timezone information

Here is my answer in Python 2.7

Print current time with timezone

from datetime import datetime
import tzlocal  # pip install tzlocal

print"%Y-%m-%d %H:%M:%S %z")

Print current time with specific timezone

from datetime import datetime
import pytz # pip install pytz

print'Asia/Taipei')).strftime("%Y-%m-%d %H:%M:%S %z")

It will print something like

2017-08-10 20:46:24 +0800

Best way to format integer as string with leading zeros?

The standard way is to use format string modifiers. These format string methods are available in most programming languages (via the sprintf function in c for example) and are a handy tool to know about.

To output a string of length 5:

... in Python 3.5 and above:

i = random.randint(0, 99999)

... Python 2.6 and above:

print '{0:05d}'.format(i)

... before Python 2.6:

print "%05d" % i


Using PropertyInfo.GetValue()

In your example propertyInfo.GetValue(this, null) should work. Consider altering GetNamesAndTypesAndValues() as follows:

public void GetNamesAndTypesAndValues()
  foreach (PropertyInfo propertyInfo in allClassProperties)
    Console.WriteLine("{0} [type = {1}] [value = {2}]",
      propertyInfo.GetValue(this, null));

ruby 1.9: invalid byte sequence in UTF-8

This seems to work:

def sanitize_utf8(string)
  return nil if string.nil?
  return string if string.valid_encoding? { |c| c.valid_encoding? }.join

How to check if Thread finished execution

It depends on how you want to use it. Using a Join is one way. Another way of doing it is let the thread notify the caller of the thread by using an event. For instance when you have your graphical user interface (GUI) thread that calls a process which runs for a while and needs to update the GUI when it finishes, you can use the event to do this. This website gives you an idea about how to work with events:

Remember that it will result in cross-threading operations and in case you want to update the GUI from another thread, you will have to use the Invoke method of the control which you want to update.

How to lock orientation of one view controller to portrait mode only in Swift

For a new version of Swift try this

override var shouldAutorotate: Bool {
    return false

override var supportedInterfaceOrientations: UIInterfaceOrientationMask {
    return UIInterfaceOrientationMask.portrait

override var preferredInterfaceOrientationForPresentation: UIInterfaceOrientation {
    return UIInterfaceOrientation.portrait

Node.js/Express.js App Only Works on Port 3000

The line you found just looks for the environmental variable PORT, if it's defined it uses it, otherwise uses the default port 3000. You have to define this environmental variable first (no need to be root)

export PORT=8080
node <your-app.js>

Convert categorical data in pandas dataframe

For a certain column, if you don't care about the ordering, use this

df['col1_num'] = df['col1'].apply(lambda x: np.where(df['col1'].unique()==x)[0][0])

If you care about the ordering, specify them as a list and use this

df['col1_num'] = df['col1'].apply(lambda x: ['first', 'second', 'third'].index(x))

Using Spring 3 autowire in a standalone Java application

Spring is moving away from XML files and uses annotations heavily. The following example is a simple standalone Spring application which uses annotation instead of XML files.

package com.zetcode.bean;

import org.springframework.stereotype.Component;

public class Message {

   private String message = "Hello there!";

   public void setMessage(String message){

      this.message  = message;

   public String getMessage(){

      return message;

This is a simple bean. It is decorated with the @Component annotation for auto-detection by Spring container.

package com.zetcode.main;

import com.zetcode.bean.Message;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.ComponentScan;

@ComponentScan(basePackages = "com.zetcode")
public class Application {

    public static void main(String[] args) {

        ApplicationContext context
                = new AnnotationConfigApplicationContext(Application.class);

        Application p = context.getBean(Application.class);

    private Message message;
    private void start() {
        System.out.println("Message: " + message.getMessage());

This is the main Application class. The @ComponentScan annotation searches for components. The @Autowired annotation injects the bean into the message variable. The AnnotationConfigApplicationContext is used to create the Spring application context.

My Standalone Spring tutorial shows how to create a standalone Spring application with both XML and annotations.

How do I perform HTML decoding/encoding using Python/Django?

See at the bottom of this page at Python wiki, there are at least 2 options to "unescape" html.

How can I autoformat/indent C code in vim?

I find that clang-format works well.

There are some example keybindings in the clang documentation

I prefer to use the equalprg binding in vim. This allows you to invoke clang-format with G=gg or other = indent options.

Just put the following in your .vimrc file:

autocmd FileType c,cpp setlocal equalprg=clang-format

Pass a PHP array to a JavaScript function

In the following example you have an PHP array, then firstly create a JavaScript array by a PHP array:

<script type="javascript">
    day = new Array(<?php echo implode(',', $day); ?>);
    week = new Array(<?php echo implode(',',$week); ?>);
    month = new Array(<?php echo implode(',',$month); ?>);

    <!--  Then pass it to the JavaScript function:   -->

    drawChart(<?php echo count($day); ?>, day, week, month);

How to modify existing XML file with XmlDocument and XmlNode in C#

You need to do something like this:

// instantiate XmlDocument and load XML from file
XmlDocument doc = new XmlDocument();

// get a list of nodes - in this case, I'm selecting all <AID> nodes under
// the <GroupAIDs> node - change to suit your needs
XmlNodeList aNodes = doc.SelectNodes("/Equipment/DataCollections/GroupAIDs/AID");

// loop through all AID nodes
foreach (XmlNode aNode in aNodes)
   // grab the "id" attribute
   XmlAttribute idAttribute = aNode.Attributes["id"];

   // check if that attribute even exists...
   if (idAttribute != null)
      // if yes - read its current value
      string currentValue = idAttribute.Value;

      // here, you can now decide what to do - for demo purposes,
      // I just set the ID value to a fixed value if it was empty before
      if (string.IsNullOrEmpty(currentValue))
         idAttribute.Value = "515";

// save the XmlDocument back to disk

Get first and last day of month using threeten, LocalDate

If anyone comes looking for first day of previous month and last day of previous month:

public static LocalDate firstDayOfPreviousMonth(LocalDate date) {
        return date.minusMonths(1).withDayOfMonth(1);

public static LocalDate lastDayOfPreviousMonth(LocalDate date) {
        return date.withDayOfMonth(1).minusDays(1);

how to set length of an column in hibernate with maximum length

You need to alter your table. Increase the column width using a DDL statement.

please see here

C# - Substring: index and length must refer to a location within the string

Try This:

 int positionOfJPG=url.IndexOf(".jpg");
 string newString = url.Substring(18, url.Length - positionOfJPG);

What are the complexity guarantees of the standard containers?

I found the nice resource Standard C++ Containers. Probably this is what you all looking for.



vector<T> v;              Make an empty vector.                                     O(1)
vector<T> v(n);           Make a vector with N elements.                            O(n)
vector<T> v(n, value);    Make a vector with N elements, initialized to value.      O(n)
vector<T> v(begin, end);  Make a vector and copy the elements from begin to end.    O(n)


v[i]          Return (or set) the I'th element.                        O(1)       Return (or set) the I'th element, with bounds checking.  O(1)
v.size()      Return current number of elements.                       O(1)
v.empty()     Return true if vector is empty.                          O(1)
v.begin()     Return random access iterator to start.                  O(1)
v.end()       Return random access iterator to end.                    O(1)
v.front()     Return the first element.                                O(1)
v.back()      Return the last element.                                 O(1)
v.capacity()  Return maximum number of elements.                       O(1)


v.push_back(value)         Add value to end.                                                O(1) (amortized)
v.insert(iterator, value)  Insert value at the position indexed by iterator.                O(n)
v.pop_back()               Remove value from end.                                           O(1)
v.assign(begin, end)       Clear the container and copy in the elements from begin to end.  O(n)
v.erase(iterator)          Erase value indexed by iterator.                                 O(n)
v.erase(begin, end)        Erase the elements from begin to end.                            O(n)

For other containers, refer to the page.

Endless loop in C/C++

Is there a certain form which one should choose?

You can choose either. Its matter of choice. All are equivalent. while(1) {}/while(true){} is frequently used for infinite loop by programmers.

How to append output to the end of a text file

Use >> instead of > when directing output to a file:

your_command >> file_to_append_to

If file_to_append_to does not exist, it will be created.


$ echo "hello" > file
$ echo "world" >> file
$ cat file 

How to enter quotes in a Java string?

suppose ROM is string variable which equals "strval" you can simply do

String value= " \" "+ROM+" \" ";

it will be stored as

value= " "strval" ";    

Jackson JSON custom serialization for certain fields

Add a @JsonProperty annotated getter, which returns a String, for the favoriteNumber field:

public class Person {
    public String name;
    public int age;
    private int favoriteNumber;

    public Person(String name, int age, int favoriteNumber) { = name;
        this.age = age;
        this.favoriteNumber = favoriteNumber;

    public String getFavoriteNumber() {
        return String.valueOf(favoriteNumber);

    public static void main(String... args) throws Exception {
        Person p = new Person("Joe", 25, 123);
        ObjectMapper mapper = new ObjectMapper();
        // {"name":"Joe","age":25,"favoriteNumber":"123"}

Cannot make file No such file or directory

File.isFile() is false if the file / directory does not exist, so you can't use it to test whether you're trying to create a directory. But that's not the first issue here.

The issue is that the intermediate directories don't exist. You want to call f.mkdirs() first.

Find everything between two XML tags with RegEx

It is not a good idea to use regex for HTML/XML parsing...

However, if you want to do it anyway, search for regex pattern


and replace it with empty string...

Android, landscape only orientation?

When you are in android studio 3 or above you need to add following lines AndroidManifest.xml file

            android:screenOrientation= "sensorLandscape"

One thing this is sensor Landscape, means it will work on both landscape sides

But if you only want to work the regular landscape side then, replace sensorLandscape to landscape

Convert Unix timestamp to a date string

If you find the notation awkward, maybe the -R-option does help. It outpouts the date in RFC 2822 format. So you won't need all those identifiers: date -d @1278999698 -R. Another possibility is to output the date in seconds in your locale: date -d @1278999698 +%c. Should be easy to remember. :-)

iOS 7's blurred overlay effect using CSS?

This pen I found the other day seemed to do it beautifully, just a bit of css and 21 lines of javascript. I hadn't heard of the cloneNode js command until I found this, but it totally worked for what I needed for sure.

Detail: A. Basically it looks at your content div and invokes a cloneNode on it so it creates a duplicate which it then places inside the overflow:hidden header object sitting on top of the page. B. Then it simply listens for scrolling so that both images seem to match and blurs the header image... annnnd BAM. Effect achieved.

Not really fully do-able in CSS until they get the lil bit of scriptability built into the language.

How to POST URL in data of a curl request

I don't think it's necessary to use semi-quotes around the variables, try:

curl -XPOST 'http://localhost/Service' -d "path=%2fxyz%2fpqr%2ftest%2f&fileName=1.doc"

%2f is the escape code for a /.

Also, do you need to specify a port? ( just checking :) )

Display MessageBox in ASP

<% response.write("<script language=""javascript"">alert('Hello!');</script>") %>

Angular2 handling http response

The service :

import 'rxjs/add/operator/map';

import { Http } from '@angular/http';
import { Observable } from "rxjs/Rx"
import { Injectable } from '@angular/core';

export class ItemService {
  private api = "your_api_url";

  constructor(private http: Http) {


  toSaveItem(item) {
    return new Promise((resolve, reject) => {
        .post(this.api + '/items', { item: item })
        .map(res => res.json())
        // This catch is very powerfull, it can catch all errors
        .catch((err: Response) => {
          // The err.statusText is empty if server down (err.type === 3)
          console.log((err.statusText || "Can't join the server."));
          // Really usefull. The app can't catch this in "(err)" closure
          reject((err.statusText || "Can't join the server."));
          // This return is required to compile but unuseable in your app
          return Observable.throw(err);
        // The (err) => {} param on subscribe can't catch server down error so I keep only the catch
        .subscribe(data => { resolve(data) })

In the app :

  (res) => { console.log('success', res) },
  (err) => { console.log('error', err) }

How to start jenkins on different port rather than 8080 using command prompt in Windows?

To change the default port of 8080. All you need to do:

  1. Goto Jenkins folder present in C:\Program Files (x86)
  2. Open a notepad or text pad and run them as administrator and then try opening the jenkins.xml file present in the jenkins folder.
  3. Change the port number as below: <arguments>-Xrs -Xmx256m -Dhudson.lifecycle=hudson.lifecycle.WindowsServiceLifecycle -jar "%BASE%\jenkins.war" --httpPort=9090</arguments>
  4. Click Save.

TSQL select into Temp table from dynamic sql

How I did it with a pivot in dynamic sql (#AccPurch was created prior to this)

DECLARE @sql AS nvarchar(MAX)
declare @Month Nvarchar(1000)

--DROP TABLE #temp
select distinct YYYYMM into #temp from #AccPurch AS ap
SELECT  @Month = COALESCE(@Month, '') + '[' + CAST(YYYYMM AS VarChar(8)) + '],' FROM    #temp

SELECT   @Month= LEFT(@Month,len(@Month)-1)

SET @sql = N'SELECT UserID, '+ @Month + N' into ##final_Donovan_12345 FROM (
Select ap.AccPurch ,
       ap.YYYYMM ,
       ap.UserID ,
FROM #AccPurch AS ap 
) p
Pivot (SUM(AccPurch) FOR YYYYMM IN ('+@Month+ N')) as pvt'

EXEC sp_executesql @sql

Select * INTO #final From ##final_Donovan_12345

DROP TABLE  ##final_Donovan_12345

Select * From #final AS f

Static constant string (class member)

Inside class definitions you can only declare static members. They have to be defined outside of the class. For compile-time integral constants the standard makes the exception that you can "initialize" members. It's still not a definition, though. Taking the address would not work without definition, for example.

I'd like to mention that I don't see the benefit of using std::string over const char[] for constants. std::string is nice and all but it requires dynamic initialization. So, if you write something like

const std::string foo = "hello";

at namespace scope the constructor of foo will be run right before execution of main starts and this constructor will create a copy of the constant "hello" in the heap memory. Unless you really need RECTANGLE to be a std::string you could just as well write

// class definition with incomplete static member could be in a header file
class A {
    static const char RECTANGLE[];

// this needs to be placed in a single translation unit only
const char A::RECTANGLE[] = "rectangle";

There! No heap allocation, no copying, no dynamic initialization.

Cheers, s.

ORA-01950: no privileges on tablespace 'USERS'

You cannot insert data because you have a quota of 0 on the tablespace. To fix this, run

ALTER USER <user> quota unlimited on <tablespace name>;


ALTER USER <user> quota 100M on <tablespace name>;

as a DBA user (depending on how much space you need / want to grant).