Given a file file.txt with the following content:
line 1
line 2
line 3
You can delete a line from file content with the d command.
The pattern to match is surrounded with default / delimiter and the d command follows the pattern:
sed '/line 2/d' file.txt
The above command will output:
l...
Whenever you declare a new rule inside another rule it is called nesting. With basic nesting, as shown below, the nested selector will be compiled as a new CSS selector with all its parents prepended, separated by a space.
// SCSS
.parent {
margin: 1rem;
.child {
float: left;
}
...
Nesting is a very powerful feature, but should be used with caution. It can happen quite easily and quickly, that you start nesting and carry on including all children in a nest, of a nest, of a nest. Let me demonstrate:
// SCSS
header {
// [css-rules]
.holder {
// [css-rules]
...
Singletons are used to ensure that only one instance of an object is being created. The singleton allows only a single instance of itself to be created which means it controls its creation.
The singleton is one of the Gang of Four design patterns and is a creational pattern.
Thread-Safe Singleton ...
Fourier Transform is probably the first lesson in Digital Signal Processing, it's application is everywhere and it is a powerful tool when it comes to analyze data (in all sectors) or signals. Matlab has a set of powerful toolboxes for Fourier Transform. In this example, we will use Fourier Transfor...
If your project depends on the external libraries, you should first install them with opam.
Assuming your dependencies are foo and bar and the main entry point of your project is foobar.ml you can then build a bytecode executable with
ocamlbuild -use-ocamlfind -pkgs 'foo,bar' foobar.byte
Warnin...
order allow,deny
deny from 255.0.0.0
allow from all
This denies access to the IP 255.0.0.0.
order allow,deny
deny from 123.45.6.
allow from all
This denies access to all IPs in the range 123.45.6.0 to 123.45.6.255.
Fortran 2003 introduced language features which can guarantee interoperability between C and Fortran (and to more languages by using C as an intermediary). These features are mostly accessed through the intrinsic module iso_c_binding:
use, intrinsic :: iso_c_binding
The intrinsic keyword here en...
For annotating some point of interest on map, we use pin annotation. Now, start by creating annotation object first.
MKPointAnnotation *pointAnnotation = [[MKPointAnnotation alloc] init];
Now provide coordinate to pointAnnotation,as
CLLocationCoordinate2D coordinate = CLLocationCoordinate2DMake...
Homebrew
You can install Node.js using the Homebrew package manager.
Start by updating brew:
brew update
You may need to change permissions or paths. It's best to run this before proceeding:
brew doctor
Next you can install Node.js by running:
brew install node
Once Node.js is installe...
Detailed instructions on getting laravel set up or installed.
composer is required for installing laravel easily.
There are 3 methods of installing laravel in your system:
Via Laravel Installer
Download the Laravel installer using composer
composer global require "laravel/installer&quo...
You can find the installers on Node.js download page. Normally, Node.js recommends two versions of Node, the LTS version (long term support) and the current version (latest release). If you are new to Node, just go for the LTS and then click the Macintosh Installer button to download the package.
I...
Several values of the same type can be returned by passing an output iterator to the function. This is particularly common for generic functions (like the algorithms of the standard library).
Example:
template<typename Incrementable, typename OutputIterator>
void generate_sequence(Increment...
Mapreduce is a part of Hadoop. So when Apache Hadoop (or any distribution of Hadoop is installed) MR is automatically installed.
MapReduce is the data processing framework over HDFS(Hadoop distributed file system). MR jobs maybe written using Java, python, Scala, R, etc.
Null coalescing is a new operator introduced in PHP 7. This operator returns its first operand if it is set and not NULL. Otherwise it will return its second operand.
The following example:
$name = $_POST['name'] ?? 'nobody';
is equivalent to both:
if (isset($_POST['name'])) {
$name = $_P...
