Tutorial by Examples: ces

There are two common ways to list all processes on a system. Both list all processes running by all users, though they differ in the format they output (the reason for the differences are historical). ps -ef # lists all processes ps aux # lists all processes in alternative format (BSD) Thi...

You can find description of the driver here. The quick example is: import psycopg2 db_host = 'postgres.server.com' db_port = '5432' db_un = 'user' db_pw = 'password' db_name = 'testdb' conn = psycopg2.connect("dbname={} host={} user={} password={}".format( ...

On systems that use the System-V style init scripts, such as RHEL/CentOS 6: service <service> start service <service> stop On systems using systemd, such as Ubuntu (Server and Desktop) >= 15.04, and RHEL/CentOS >= 7: systemctl <service> dnsmasq systemctl <service> ...

You can place named arguments in any order you want. Sample Method: public static string Sample(string left, string right) { return string.Join("-",left,right); } Call Sample: Console.WriteLine (Sample(left:"A",right:"B")); Console.WriteLine (Sample(right...

It is illegal to access a reference to an object that has gone out of scope or been otherwise destroyed. Such a reference is said to be dangling since it no longer refers to a valid object. #include <iostream> int& getX() { int x = 42; return x; } int main() { int& r...

Pair allows us to treat two objects as one object. Pairs can be easily constructed with the help of template function std::make_pair. Alternative way is to create pair and assign its elements (first and second) later. #include <iostream> #include <utility> int main() { std::p...

Copy the package installer unit file to /etc where changes will not be overwritten on an upgrade: cp /lib/systemd/system/docker.service /etc/systemd/system/docker.service Update /etc/systemd/system/docker.service with your options on ExecStart: ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0...

Xamarin.Forms provide great mechanism for styling your cross-platforms application with global styles. In mobile world your application must be pretty and stand out from the other applications. One of this characters is Custom Fonts used in application. With power support of XAML Styling in Xamar...

First let's create an ExchangeManager object, where the constructor will connect to the services for us. It also has a GetOofSettings method, which will return the OofSettings object for the specified email address : using System; using System.Web.Configuration; using Microsoft.Exchange.WebServic...

To reference a variable in a query, add a colon (:) before the variable name. Datetime targetDate = Datetime.now().addDays(-7); List<Lead> recentLeads = [SELECT Id FROM Lead WHERE CreatedDate > :targetDate]; string targetName = 'Unknown'; List<Contact> incompleteContacts = [SELE...

<?php use Symfony\Bundle\FrameworkBundle\Controller\Controller; use Symfony\Component\HttpFoundation\Request; class TestController extends Controller { //Inject Request HTTP Component in your function then able to exploit it public function myFunctionAction(Request $request) {...

Individual elements can be accessed through indexes. Python arrays are zero-indexed. Here is an example : my_array = array('i', [1,2,3,4,5]) print(my_array[1]) # 2 print(my_array[2]) # 3 print(my_array[0]) # 1

count() will return the number of times and element appears in an array. In the following example we see that the value 3 occurs twice. my_array = array('i', [1,2,3,3,5]) my_array.count(3) # 2

<!-- file.xml --> <people> <person id="101"> <name>Jon Lajoie</name> <age>22</age> </person> <person id="102"> <name>Lord Gaben</name> <age>65</age> ...

Classes can implement more than one interface, as opposed to inheriting from more than one class (Multiple Inheritance) which isn't possible for Delphi classes. To achieve this, the name of all interfaces must be added comma-separated behind the base class. Of course, the implementing class must al...

Interfaces can inherit from each other, exactly like classes do, too. An implementing class thus has to implement functions of the interface and all base interfaces. This way, however, the compiler doesn't know that the implenting class also implements the base interface, it only knows of the interf...

Since the declaration of variables in interfaces isn't possible, the "fast" way of defining properites (property Value: TObject read FValue write FValue;) can't be used. Instead, the Getter and setter (each only if needed) have to be declared in the interface, too. IInterface = interface(...

The auto keyword by itself represents a value type, similar to int or char. It can be modified with the const keyword and the & symbol to represent a const type or a reference type, respectively. These modifiers can be combined. In this example, s is a value type (its type will be inferred as s...

Some devices connected through a serial port send data to your program at a constant rate (streaming data) or send data at unpredictable intervals. You can configure the serial port to execute a function automatically to handle data whenever it arrives. This is called the "callback function&quo...

Resolving scoped services during application startup can be difficult, because there is no request and hence no scoped service. Resolving a scoped service during application startup via app.ApplicationServices.GetService<AppDbContext>() can cause issues, because it will be created in the sc...