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To assign variables from the command-line, -v can be used: $ awk -v myvar="hello" 'BEGIN {print myvar}' hello Note that there are no spaces around the equal sign. This allows to use shell variables: $ shell_var="hello" $ awk -v myvar="$shell_var" 'BEGIN {print m...

Node Version Manager, otherwise known as nvm, is a bash script that simplifies the management of multiple Node.js versions. To install nvm, use the provided install script: $ curl -o- https://raw.githubusercontent.com/creationix/nvm/v0.31.3/install.sh | bash For windows there is a nvm-windows p...

Rcpp Attributes makes the process of working with R and C++ straightforward. The form of attributes take: // [[Rcpp::attribute]] The use of attributes is typically associated with: // [[Rcpp::export]] that is placed directly above a declared function header when reading in a C++ file via sou...

In some cases you may want to wrap a synchronous operation inside a promise to prevent repetition in code branches. Take this example: if (result) { // if we already have a result processResult(result); // process it } else { fetchResult().then(processResult); } The synchronous and async...

Cloning a huge repository (like a project with multiple years of history) might take a long time, or fail because of the amount of data to be transferred. In cases where you don't need to have the full history available, you can do a shallow clone: git clone [repo_url] --depth 1 The above comman...

Similarly to the SimpleXML, you can use DOMDocument to parse XML from a string or from a XML file 1. From a string $doc = new DOMDocument(); $doc->loadXML($string); 2. From a file $doc = new DOMDocument(); $doc->load('books.xml');// use the actual file path. Absolute or relative Exa...

When you want to use user generated content in the SQL, it with done with parameters. For example for searching user with the name aminadav you should do: var username = 'aminadav'; var querystring = 'SELECT name, email from users where name = ?'; connection.query(querystring, [username], functi...

a. Running multiple queries at same time All queries in MySQL connection are done one after another. It means that if you want to do 10 queries and each query takes 2 seconds then it will take 20 seconds to complete whole execution. The solution is to create 10 connection and run each query in a di...

You send the query as a string and in response callback with the answer is received. The callback gives you error, array of rows and fields. Each row contains all the column of the returned table. Here is a snippet for the following explanation. connection.query('SELECT name,email from users', fu...

git checkout --orphan new-orphan-branch The first commit made on this new branch will have no parents and it will be the root of a new history totally disconnected from all the other branches and commits. source

You can use a RecyclerView.ItemDecoration to put extra margins around each item in a RecyclerView. This can in some cases clean up both your adapter implementation and your item view XML. public class MyItemDecoration extends RecyclerView.ItemDecoration { private final int extraMargin; ...

You can use any element as an handle to drag another element around: <script> $(function() { $( "#draggable" ).draggable({ handle: ".handle" }); }); </script> <div id="draggable"> <span class="handle"&...

Once your setup.py is fully functional (see Introduction), it is very easy to upload your package to PyPI. Setup a .pypirc File This file stores logins and passwords to authenticate your accounts. It is typically stored in your home directory. # .pypirc file [distutils] index-servers = py...

Retrofit requests can be logged using an intercepter. There are several levels of detail available: NONE, BASIC, HEADERS, BODY. See Github project here. Add dependency to build.gradle: compile 'com.squareup.okhttp3:logging-interceptor:3.8.1' Add logging interceptor when creating Retrofit:...

You can group multiple boolean logic statements within parenthesis in order to create a more complex logic evaluation, especially useful in if statements. if ((age >= 18 && height >= 5.11) || (status === 'royalty' && hasInvitation)) { console.log('You can enter our club'); ...

__call() and __callStatic() are called when somebody is calling nonexistent object method in object or static context. class Foo { /** * This method will be called when somebody will try to invoke a method in object * context, which does not exist, like: * * $foo->...

__sleep and __wakeup are methods that are related to the serialization process. serialize function checks if a class has a __sleep method. If so, it will be executed before any serialization. __sleep is supposed to return an array of the names of all variables of an object that should be serializ...

With Blade, you can also include partial views (called 'partials') directly into a page like so: @include('includes.info', ['title' => 'Information Station']) The code above will include the view at 'views/includes/info.blade.php'. It will also pass in a variable $title having value 'Informat...

Subclassing UIControl gives us access to the following methods: beginTrackingWithTouch is called when the finger first touches down within the control's bounds. continueTrackingWithTouch is called repeatedly as the finger slides across the control and even outside of the control's bounds. endTr...

With local image Swift let image = UIImage(named: "imageFromBundleOrAsset") Objective-C UIImage *image = [UIImage imageNamed:@"imageFromBundleOrAsset"]; Note The method imageNamed caches the image's contents to memory. Loading many large images that way can cause low...