{"id":391704,"date":"2024-06-29T09:58:58","date_gmt":"2024-06-29T09:58:58","guid":{"rendered":"http:\/\/savepearlharbor.com\/?p=391704"},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-29T21:00:00","slug":"","status":"publish","type":"post","link":"https:\/\/savepearlharbor.com\/?p=391704","title":{"rendered":"Building your own CLI with Swift Programming Language<\/span>"},"content":{"rendered":"
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Command-line interfaces (CLI) are a common way to use applications. In iOS, we usually use scripting languages like Bash or Ruby to build those CLIs and automate mundane tasks. The most popular CLI for app signing and build automation is, without a doubt, Fastlane<\/a>, which was initially written in Ruby. Fastlane is a great tool, convenient and fairly easy to use, and a lot of effort came into building it.<\/p>\n

However, there’s a great chance you considered moving away from Fastlane to avoid learning Ruby and to lower the entry threshold for your developers. Setting up a Ruby environment could be quite tedious and require additional devs’ expertise to write and support those scripts. <\/p>\n

Also, Fastlane comes with a lot of dependencies itself. There are 200+ lines in Gemfile.lock<\/code> describing dependencies.<\/p>\n

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And that’s just a part of that list.<\/p>\n\n

To counter that, we can use our currently most popular language in iOS \u2013 Swift. As a multipurpose language, Swift allows us to write not only apps, but also backend, scripts, and, specifically, command line tools. <\/p>\n

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An interesting note on Fastlane \u2013 they are adding<\/a> the Swift version of their tools. It’s currently in beta, and most times it’s just a bridge to Ruby code. <\/p>\n<\/blockquote>\n

1. Setting up the project<\/h2>\n

The hard way<\/h3>\n

The first alternative would be to create a project in Xcode and use the Command line tool<\/code> template. Without any additional dependencies, we could create a Script.swift<\/code> file and add code like this:<\/p>\n

import Foundation  let arguments = CommandLine.arguments  guard      arguments.count == 3,     let num1 = Int(arguments[1]), let num2 = Int(arguments[2])  else {         print(\"Usage: add <num1> <num2>\")         exit(1) }  let result = num1 + num2 print(result)<\/code><\/pre>\n
This simple example wouldn’t need compiling and could be executed as a script. We only need to add a swift environment to our script like so:<\/p>\n
#!\/usr\/bin\/env swift<\/code><\/pre>\n
It implies you have Xcode command line tools or a separate swift<\/code> runtime installed. We should also make our file executable and give it all the needed permissions to run:<\/p>\n