Learn Grep, Ios and Ruby

CMD+F in your text editor can only get you so far! In this course, we will learn to use grep and find, two powerful command-line utilities, to search through and explore our codebase. Learn to search specific files and folders, using regular expressions to look for -- or ignore! -- particular phrases. We'll cover how to search recursively, get more context on your results, and some simple tricks to make your searches faster and more targeted.


Once you're familiar with grep and find, you'll be able to quickly answer questions such as: Do I use this function anywhere other than my tests? Where does this file get imported? Whether you're working on a new feature, reading a codebase for the first time, or refactoring existing code, grep and find can help you work faster and more effectively.

A Unix command used to search files for the occurrence of a string of characters that matches a specified pattern.

grep

Use Grep for Fast Search from the Command Line

Open source framework for building truly native mobile apps with Angular, TypeScript or JavaScript.

nativescript

Objective C is a very interesting programming language which offers a lot of power as well as interesting paradigms. Let’s look at some Objective C api’s and how they translate to NativeScript. In particular, let’s learn how to wire up iOS delegates using [Filestack's FSPickerDelegate](https://github.com/filestack/FSPicker#fspickerdelegate) as an example. We will also look at handling WeakRef’s and iterating an NSArray.

Use Objective C Delegates in NativeScript for Angular iOS apps

One of the exciting benefits you have with NativeScript is the ability to write native code (Java and Objective C) directly in JavaScript/TypeScript allowing you to create a consistent high level api over top of both underlying iOS Objective C/Swift and Android Java apis. In this lesson, we will look at how to design a consistent api that taps into the appropriate native api’s on the target platforms using underlying native libraries.

Develop a consistent plugin api across your Android and iOS NativeScript app

Rails is a web-application framework that includes everything needed to create database-backed web applications according to the Model-View-Controller (MVC) pattern.

rails

Expanding on [Part 1](https://egghead.io/lessons/angularjs-rails-todo-api-part-1), this lesson will look at how to bootstrap AngularJS in a rails application as part of the asset pipeline. With Angular available, you'll see how to communicate with the Rails API using $resource.

Rails Todo API Part 2

To prepare your development environment to code against native apis such as Objective C, Swift and Java, let's learn how to [install tns-platform-declarations](https://www.npmjs.com/package/tns-platform-declarations) to provide rich intellisense support for all the native iOS and Android api’s. This lesson will cover how to modify your tsconfig.json and references.d.ts properly to ensure working with native api’s is smooth and as helpful as possible.

Prepare for native iOS and Android api intellisense with NativeScript

Sometimes you'll be looking for a string, but won't know which file it's in; or you'll want to find all usages of it within a directory. Learn how to use grep -r to recursively search all the files in a directory. 

Search directory contents recursively using grep

Learn how to use find to identify filenames matching specified patterns. We'll use find to identify all .jsx files in a directory, or all test files in a directory.

Use find to search for filename patterns

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

In this lesson we'll explore debugging our React Native application in an actual iOS device.

React Native: Debugging on an iOS Device

Learn to use git grep to only search through the tracked files in a git repo. This is especially useful when you want to exclude build artifacts or locally installed dependencies, such as webpack bundles or the node_modules directory. You'll also note that git grep is automatically colorized - we'll see how to get the same coloring effect with grep --color.

Search the contents of a git repository with git grep

By default, grep displays the file path and the line where a match is found. Learn to use the flags -A, -B, -C, and -n to get more context, and view line numbers as well as the lines surrounding a pattern match.


Show context around matches using grep

By using wildcards and glob patterns with the special characters . and *, you can create regular expressions that describe what kind of text you're looking for, instead of just plaintext strings. 

Search for basic patterns using grep

We will learn how to install an Objective C library distributed via a [CocoaPod](https://cocoapods.org) into our project and expose its native api to our app. Specifically, we will cover how to immediately start working with the library even when a [NativeScript](/q/nativescript) plugin does not exist for it. Take for example [Filestack](https://filestack.com), a really powerful file uploading api that provides an SDK written in [JavaScript](/q/javascript) for the web, but also offers native SDK's for iOS and Android. Let's take a look at how to code right against this [native iOS SDK](https://filestack.com/docs/sdks/ios).

Use an Objective C library in NativeScript for Angular iOS app

Learn to use grep's extended regular expressions to describe more complex patterns. The `?` and `+` special characters describe optional patterns. The `?` character matches zero or one instance of the preceding term, and the `+` character matches one or more instances of the preceding term. To use these characters, you'll need to either escape them with backslashes or turn on extended regular expressions with the `-E` flag.

Use grep's extended regular expressions to find complex patterns

Learn to use the special anchor characters `^` and `$` to indicate the beginning and end of lines when writing regular expressions for grep. These line anchors are part of basic regular expressions in grep, so you don't need to escape them.

Specify line beginning and end in patterns using grep

You can describe classes of characters using bracket expressions. We'll use expressions such as [a-zA-Z] and [0-9] to search for alphabetic and numeric characters with grep.

Match classes of characters using bracket expressions with grep

In this lesson we'll look at some simple ways to customize TabBarIOS, creating a scrollable tab area, and implementing custom icons in TabBarIOS.Item.

React Native: TabBarIOS Customization

Describe optional patterns with grep OR using the vertical bar character `|`. By using the `|` special character, you can write either-or style patterns. In this lesson we'll look for matches on "grey" or "gray". Like the `+` and `?` characters, the `|` character is part of extended regular expressions with grep, so you'll either need to escape it with a backslash, or use the -E flag.

Search for optional patterns with grep OR

Learn how to generate TypeScript declaration files for all native api’s for iOS, including any 3rd party Objective C/Swift libraries included in your project via Cocoapods or other means. This will allow you to view all the metadata for included iOS libraries to see what classes and apis are exposed to NativeScript.

Generate metadata TypeScript declarations for Objective C/Swift libraries on iOS

Building a custom NativeScript XML view component for iOS entails several interesting notes, like overriding the onLoaded method of the base NativeScript View class. Let’s look at how to properly build a custom component based on an underlying native view widget with NativeScript XML which may come from a CocoaPod. We will learn several important aspects regarding Objective C properties and methods you will need to consider. In particular, we will implement this [Objective C view component](https://github.com/Boris-Em/BEMAnalogClock)

Build a custom NativeScript view component for iOS

By grouping your searches with parentheses, you can create even more complex searches. Grouping lets you separate out different parts of your regular expression, and apply special characters like +, ?, and * to groups of search terms.

Search with groups using grep

 Learn the basic syntax for using grep to search the contents of a single file or files. It's like CMD+F, but better! You'll be able to quickly see all matching results in a file.

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