Tutorial by Examples: b

HTTP Basic Authentication provides a straightforward mechanism for authentication. Credentials are sent in plain text, and so is insecure by default. Successful authentication proceeds as follows. The client requests a page for which access is restricted: GET /secret The server responds with st...

Download your preferred version from Lightbend with curl: curl -O http://downloads.lightbend.com/scala/2.xx.x/scala-2.xx.x.tgz Unzip the tar file to /usr/local/share or /opt/bin: unzip scala-2.xx.x.tgz mv scala-2.xx.x /usr/local/share/scala Add the PATH to ~/.profile or ~/.bash_profile or ...

Case classes provide a copy method that creates a new object that shares the same fields as the old one, with certain changes. We can use this feature to create a new object from a previous one that has some of the same characteristics. This simple case class to demonstrates this feature: case cla...

A Subject in RxJava is a class that is both an Observable and an Observer. This basically means that it can act as an Observable and pass inputs to subscribers and as an Observer to get inputs from another Observable. Subject<String, String> subject = PublishSubject.create(); subject.subscr...

PublishSubject emits to an Observer only those items that are emitted by the source Observable subsequent to the time of the subscription. A simple PublishSubject example: Observable<Long> clock = Observable.interval(500, TimeUnit.MILLISECONDS); Subject<Long, Long> subjectLong = Publi...

You can have a dependency with a single jar or multiple jar files. With a single jar file you can add: dependencies { compile files('libs/local_dependency.jar') } It's possible to add a directory of jars to compile. dependencies { compile fileTree(dir: 'libs', include: ['*.jar']...

You can add remote dependencies in Gradle usign this structure: compile 'group:name:version' or this alternative syntax: compile group: 'xxx', name: 'xxxxx', version: 'xxxx' For example: compile 'com.android.support:appcompat-v7:24.1.0' The compile 'com.android.support:appcompat-v7:24.1....

{ "description": "My awesome library", "dependencies": { }, "frameworks": { "net40": { }, "netstandard1.3": { "dependencies": { "NETStandard.Library": "1.6.0" ...

Actually any value different from NIL is considered a true value in Common Lisp. For instance: CL-USER> (let ((a (+ 2 2))) (if a a "Oh my! 2 + 2 is equal to NIL!")) 4 This fact can be combined with the boolean operators to make programs m...

R has a number of build in constants. The following constants are available: LETTERS: the 26 upper-case letters of the Roman alphabet letters: the 26 lower-case letters of the Roman alphabet month.abb: the three-letter abbreviations for the English month names month.name: the English names fo...

Any ASCII editor can edit batch files. A list of editors that can syntax highlight batch syntax can be found here. You can also use the default notepad shipped with windows to edit and view a batch file, although it does not offer syntax highlighting. To open notepad: Press Win 𐌎+R, type notepa...

I have the following list: 1. Alon Cohen 2. Elad Yaron 3. Yaron Amrani 4. Yogev Yaron I want to select the first name of the guys with the Yaron surname. Since I don't care about what number it is I'll just put it as whatever digit it is and a matching dot and space after it from the beginni...

One could easily center a child element using table display property. HTML <div class="wrapper"> <div class="parent"> <div class="child"></div> </div> </div> CSS .wrapper { display: table; vertica...

Cache-control: no-store Instructs clients no to cache the response in any way, and to forget it at soon as possible. This directive was originally designed for sensitive data (today HTTPS should be used instead), but can be used to avoid polluting caches with responses that can't be reused. It...

Expires — specifies date when the resource becomes stale. It relies on servers and clients having accurate clocks and supporting time zones correctly. Cache-control: max-age takes precedence over Expires, and is generally more reliable. post-check and pre-check directives are non-standard I...

Many commands and programs in the remote side are screen-based (e.g. mc) or they need to ask password (e.g. sudo), to be able to run these kind of programs you can use option -t. ssh -t [email protected] sudo ls / [sudo] password for alice: bin root dev etc home lib mnt opt proc root run usr ...

Fabric is a Python (2.5-2.7) library and command-line tool for streamlining the use of SSH for application deployment or systems administration tasks. It lets you execute arbitrary Python functions via the command line. Install fabric via pip install fabric Create fabfile.py in your root directory...

foldMap maps each element of the Foldable structure to a Monoid, and then combines them into a single value. foldMap and foldr can be defined in terms of one another, which means that instances of Foldable need only give a definition for one of them. class Foldable t where foldMap :: Monoid m...

NSArray *myColors = @[@"Red", @"Green", @"Blue", @"Yellow"]; [myColors enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) { NSLog(@"enumerating object %@ at index %lu", obj, idx); }]; By setting the stop parameter to YES you c...

As parameters (8, 16, 32 bits) 8, 16, 32 bits integers are always passed, on the stack, as full width 32 bits values1. No extension, signed or zeroed, is needed. The callee will just use the lower part of the full width values. //C prototype of the callee void __attribute__((cdecl)) foo(char ...