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This variable is used to set input record separator, by default a newline. awk 'BEGIN{RS=","} {print $0}' file

This variable is used to set output record separator, by default a newline. awk 'BEGIN{ORS=","} {print $0}' file

Exit status 0: success Exit status other than 0: failure To test on the exit status of a command: if command;then echo 'success' else echo 'failure' fi

Press controlr and type a pattern. For example, if you recently executed man 5 crontab, you can find it quickly by starting to type "crontab". The prompt will change like this: (reverse-i-search)`cr': man 5 crontab The `cr' there is the string I typed so far. This is an incremental s...

A classic use of here documents is to create a file by typing its content: cat > fruits.txt << EOF apple orange lemon EOF The here-document is the lines between the << EOF and EOF. This here document becomes the input of the cat command. The cat command simply outputs its in...

expr or Evaluate expressions evaluates an expression and writes the result on standard output Basic arithmetics expr 2 + 3 5 When multiplying, you need to escape the * sign expr 2 \* 3 6 You can also use variables a=2 expr $a + 3 5 Keep in mind that it only supports integers, so exp...

Most of the built-in operators (including conversion operators) can be overloaded by using the operator keyword along with the public and static modifiers. The operators comes in three forms: unary operators, binary operators and conversion operators. Unary and binary operators requires at least o...

Setup First, install the necessary packages with: npm install express cors mongoose Code Then, add dependencies to server.js, create the database schema and the name of the collection, create an Express.js server, and connect to MongoDB: var express = require('express'); var cors = require('...

Use $this to refer to the current object. Use self to refer to the current class. In other words, use $this->member for non-static members, use self::$member for static members. In the example below, sayHello() and sayGoodbye() are using self and $this difference can be observed here. cl...

The factorial of a number (denoted with !, as for instance 9!) is the multiplication of that number with the factorial of one lower. So, for instance, 9! = 9 x 8! = 9 x 8 x 7! = 9 x 8 x 7 x 6 x 5 x 4 x 3 x 2 x 1. So in code that becomes, using recursion: long Factorial(long x) { if (x < 1...

You can create temporary files which has a visible name on the file system which can be accessed via the name property. The file can, on unix systems, be configured to delete on closure (set by delete param, default is True) or can be reopened later. The following will create and open a named temp...

As we know we can declare an array with default values: int[] arr = new int[10]; This will create an array of 10 integers with each element of the array having value 0 (the default value of type int). To create an array initialized with a non-default value, we can use Enumerable.Repeat from the...

Event delegation is a process which allow us to avoid adding event listeners to specific nodes; instead, the event listener is added to parent node. This mechanism utilizes the event propagation/bubbling to handle an event at a higher level element/node in the DOM instead of using the element on whi...

You might have heard that everything in Python is an object, even literals. This means, for example, 7 is an object as well, which means it has attributes. For example, one of these attributes is the bit_length. It returns the amount of bits needed to represent the value it is called upon. x = 7 ...

<svg width="800px" height="600px"> <defs> <filter id="greyscale"> <feColorMatrix type="matrix" values="0.2126 0.7152 0.0722 0 0 0.2126 0.7152 0.0722 0 0 0...

<svg width="800px" height="600px"> <defs> <filter id="greyscale"> <feColorMatrix type="matrix" values="0 1 0 0 0 0 1 0 0 0 0 1 0 0 0 ...

<svg width="800px" height="600px"> <defs> <filter id="greyscale"> <feColorMatrix type="matrix" values=".2 .2 .2 0 0 .6 .6 .6 0 0 .2 .2 .2 0 0 ...

OVERVIEW cocos2d-x is an open source, cross-platform game engine. It allows developers to code in C++, Lua and Javascript deployment into iOS, Android, Windows Phone, Mac OS X, Windows Desktop and Linux. PREREQUISITES Build Requirements Mac OS X 10.7+, Xcode 4.6+ Windows 7+, VS 2012+ Ubunt...

To produce nested JSON object, you need to simply add one JSON object to another: JSONObject mainObject = new JSONObject(); // Host object JSONObject requestObject = new JSONObject(); // Included object try { requestObject.put("lastname", lastname); reques...

Create a node CREATE (neo:Company) //create node with label 'Company' CREATE (neo:Company {name: 'Neo4j', hq: 'San Mateo'}) //create node with properties Create a relationship CREATE (beginning_node)-[:edge_name{Attribute:1, Attribute:'two'}]->(ending_node) Query Templates Running neo...