Tutorial by Examples: e

Cloning a file using streams

This program illustrates how one can copy a file using readable and writable streams using the createReadStream(), and createWriteStream() functions provided by the file system module. //Require the file System module var fs = require('fs'); /* Create readable stream to file in current direc...

Node.js • Filesystem I/O

Hello World

This is your cluster.js: const cluster = require('cluster'); const http = require('http'); const numCPUs = require('os').cpus().length; if (cluster.isMaster) { // Fork workers. for (let i = 0; i < numCPUs; i++) { cluster.fork(); } cluster.on('exit', (worker, code, signal)...

Node.js • Cluster Module

Produce a patch-compatible diff

Sometimes you just need a diff to apply using patch. The regular git --diff does not work. Try this instead: git diff --no-prefix > some_file.patch Then somewhere else you can reverse it: patch -p0 < some_file.patch

Git • Git Diff

JSON API with ExpressJS

var express = require('express'); var cors = require('cors'); // Use cors module for enable Cross-origin resource sharing var app = express(); app.use(cors()); // for all routes var port = process.env.PORT || 8080; app.get('/', function(req, res) { var info = { 'string_value...

Node.js • Web Apps With Express

Building your own modules

You can also reference an object to publicly export and continuously append methods to that object: const auth = module.exports = {} const config = require('../config') const request = require('request') auth.email = function (data, callback) { // Authenticate with an email address } au...

Node.js • Exporting and Consuming Modules

Handling Exception In Node.Js

Node.js has 3 basic ways to handle exceptions/errors: try-catch block error as the first argument to a callback emit an error event using eventEmitter try-catch is used to catch the exceptions thrown from the synchronous code execution. If the caller (or the caller's caller, ...) used try/ca...

Node.js • Exception handling

Completely uninstall Node.js on Mac OSX

In Terminal on your Mac operating system, enter the following 2 commands: lsbom -f -l -s -pf /var/db/receipts/org.nodejs.pkg.bom | while read f; do sudo rm /usr/local/${f}; done sudo rm -rf /usr/local/lib/node /usr/local/lib/node_modules /var/db/receipts/org.nodejs.*

Node.js • Uninstalling Node.js

Perfectly aligned buttons inside cards with flexbox

It's a regular pattern in design these days to vertically align call to actions inside its containing cards like this: This can be achieved using a special trick with flexbox HTML <div class="cards"> <div class="card"> <p>Lorem ipsum Magna proident ...

CSS • Flexible Box Layout (Flexbox)

Setting up a Theme

First we need to reference the Styles we want to use. <link rel="stylesheet" href="[file path]/kendo.common.min.css" /> <link rel="stylesheet" href="[file path]/kendo.[Theme].min.css" /> Now most of the controls use the [Theme], given in the a...

kendo-ui • Themes

Join across cores

{!join from=personid to=id fromIndex=AddressCore}address:Address1 So if you have two cores that look like this: PersonCore - id, name AddressCore - id, address, personid This will find all PersonCore documents at a specific address

solr • Lucene Query Syntax

Hello world program

This is a shell session showing how to create a "Hello world" program and run it with Cargo: $ cargo new hello --bin $ cd hello $ cargo run Compiling hello v0.1.0 (file:///home/rust/hello) Running `target/debug/hello` Hello, world! After doing this, you can edit the progra...

Rust • Cargo

Iterating through causes

It is often useful for debugging purposes to find the root cause of an error. In order to examine an error value that implements std::error::Error: use std::error::Error; let orig_error = call_returning_error(); // Use an Option<&Error>. This is the return type of Error.cause(). le...

Rust • Error handling

Log for a range of lines within a file

$ git log -L 1,20:index.html commit 6a57fde739de66293231f6204cbd8b2feca3a869 Author: John Doe <[email protected]> Date: Tue Mar 22 16:33:42 2016 -0500 commit message diff --git a/index.html b/index.html --- a/index.html +++ b/index.html @@ -1,17 +1,20 @@ <!DOCTYPE HTML> ...

Git • Browsing the history

The Pass Statement

pass is a null statement for when a statement is required by Python syntax (such as within the body of a for or while loop), but no action is required or desired by the programmer. This can be useful as a placeholder for code that is yet to be written. for x in range(10): pass #we don't want t...

Python Language • Loops

Changing the author of commits

You can use an environment filter to change the author of commits. Just modify and export $GIT_AUTHOR_NAME in the script to change who authored the commit. Create a file filter.sh with contents like so: if [ "$GIT_AUTHOR_NAME" = "Author to Change From" ] then export GIT_A...

Git • Rewriting history with filter-branch

Validate IP Addresses

Validates a value is a valid IP address var_dump(filter_var('185.158.24.24', FILTER_VALIDATE_IP)); var_dump(filter_var('2001:0db8:0a0b:12f0:0000:0000:0000:0001', FILTER_VALIDATE_IP)); var_dump(filter_var('192.168.0.1', FILTER_VALIDATE_IP)); var_dump(filter_var('127.0.0.1', FILTER_VALIDATE_IP)); ...

PHP • Filters & Filter Functions

Taking a screenshot and video (for kitkat only) from a device display

Screen shot: Option 1 (pure adb) The shell adb command allows us to execute commands using a device's built-in shell. The screencap shell command captures the content currently visible on a device and saves it into a given image file, e.g. /sdcard/screen.png: adb shell screencap /sdcard/screen.png...

Android • ADB (Android Debug Bridge)

Recording the display

4.4 Recording the display of devices running Android 4.4 (API level 19) and higher: adb shell screenrecord [options] <filename> adb shell screenrecord /sdcard/demo.mp4 (press Ctrl-C to stop recording) Download the file from the device: adb pull /sdcard/demo.mp4 Note: Stop the scre...

Android • adb shell

Absolute/Relative Imports

In Python 3, PEP 404 changes the way imports work from Python 2. Implicit relative imports are no longer allowed in packages and from ... import * imports are only allowed in module level code. To achieve Python 3 behavior in Python 2: the absolute imports feature can be enabled with from __futu...

Python Language • Incompatibilities moving from Python 2 to Python 3

Implementation using RuntimeInitializeOnLoadMethodAttribute

Since Unity 5.2.5 it's possible to use RuntimeInitializeOnLoadMethodAttribute to execute initialization logic bypassing MonoBehaviour order of execution. It provides a way to create more clean and robust implementation: using UnityEngine; sealed class GameDirector : MonoBehaviour { // Beca...

unity3d • Singletons in Unity