Tutorial by Examples: d

Usually output of a command goes to the terminal. Using the concept of Output redirection, the output of a command can be redirected to a file. So insted of displaying the output to the terminal it can be send to a file. '>' character is used for output redirection. $ pwd > file1 $ cat file...

The commands normally take their input from the standard input device keyboard. Using Input redirection concept, we can have their input redirected from a file. To redirect standard input from a file instead of the keyboard, the '<' character is used. $ cat file1 monday tuesday wednsday th...

type state_t is (START, READING, WRITING); -- user-defined enumerated type

Step 1 : Install the node-inspector package using npm globally on you machine $ npm install -g node-inspector Step 2 : Start the node-inspector server $ node-inspector Step 3 : Start debugging your node application $ node --debug-brk your/short/node/script.js Step 4 : Open http://127.0....

Is raised when you tried to use a variable, method or function that is not initialized (at least not before). In other words, it is raised when a requested local or global name is not found. It's possible that you misspelt the name of the object or forgot to import something. Also maybe it's in anot...

If all you need is serializing mongo results into json, it is possible to use the json module, provided you define custom handlers to deal with non-serializable fields types. One advantage is that you have full power on how you encode specific fields, like the datetime representation. Here is a ha...

Import a Mongoose Model (See topic "Mongoose Schemas") var User = require("../models/user-schema.js") The findOne method will return the first entry in the database that matches the first parameter. The parameter should be an object where the key is the field to look for and th...

new Vue({ el:"#app", data:{ foo: "bar" }, methods:{ doSomethingAsynchronous(){ setTimeout(function(){ // This is wrong! Inside this function, // "this" refers to the window object. this.foo = "baz"; ...

new Vue({ el:"#star-wars-people", data:{ people: null }, mounted: function(){ $.getJSON("http://swapi.co/api/people/", function(data){ // Again, this is wrong! "this", here, refers to the window. this.people = data.results; }) ...

You can bind the callback function. new Vue({ el:"#star-wars-people", data:{ people: null }, mounted:function(){ $.getJSON("http://swapi.co/api/people/", function(data){ this.people = data.results; }.bind(this)); } })

new Vue({ el:"#app", data:{ foo: "bar" }, methods:{ // This is wrong! Arrow functions capture "this" lexically // and "this" will refer to the window. doSomething: () => this.foo = "baz" } })

new Vue({ el:"#app", data:{ foo: "bar" }, methods:{ doSomething: function(){ this.foo = "baz" } } }) Alternatively, if you are using a javascript compiler or a browser that supports Ecmascript 2015 new Vue({ el:"#app&quo...

This example shows how you can install and run WSO2 API Manager in your machine. For this example API Manager 2.1.0 version is used. You can install WSO2 API Manager in two ways. Download the API Manager product from product website. Checkout the source code from GitHub, build the source code ...

If a file may contain Windows or Unix-like line endings (or even a mixture of both) then the intended text replacement may not work as expected. Sample: $ echo -e 'Entry 1\nEntry 2.1\tEntry 2.2\r\nEntry 3\r\n\r\n' \ > | awk -F'\t' '$1 != "" { print $1 }' \ > | hexdump -c 0000000...

Opening a stream fopen opens a file stream handle, which can be used with various functions for reading, writing, seeking and other functions on top of it. This value is of resource type, and cannot be passed to other threads persisting its functionality. $f = fopen("errors.log", "a...

Copying files copy copies the source file in the first argument to the destination in the second argument. The resolved destination needs to be in a directory that is already created. if (copy('test.txt', 'dest.txt')) { echo 'File has been copied successfully'; } else { echo 'Failed to ...

Steps: Create Empty .Net Core Web App: Go to wwwroot, and create a normal html page called Index.html: Configure Startup.cs to accept static files (this will require to add "Microsoft.AspNetCore.StaticFiles": "1.0.0" library in the “project.json” file): ...

public class Person { private final String salutation; private final String firstName; private final String middleName; private final String lastName; private final String suffix; private final Address address; private final boolean isFemale; private final boolean isEmployed; private final ...

List can contain n number of items. The items in list are separated by comma >> a = [1,2,3] To access an element in the list use the index. The index starts from 0 >> a[0] >> 1 Lists can be nested. >> nested_list = [ [1,2,3], ['a','b','c'] ] >> nested_list...

Here counter is a child component accessed by demo which is a parent component using v-model. // child component Vue.component('counter', { template: `<div><button @click='add'>+1</button> <button @click='sub'>-1</button> <div>this is inside the child c...