原文:
https://www.raywenderlich.com/128039/command-line-programs-os-x-tutorial

练习写的代码:

https://github.com/uniquejava/Panagram

知识点:

取程序名
let executableName = (Process.arguments[0] as NSString).lastPathComponent

取命令行参数个数
let argCount = Process.argc

取参数数组(比如第一个参数)
let argument = Process.arguments[1]

字符串操作
截取
argument.substringFromIndex(argument.startIndex.advancedBy(1)))

替换:
self.lowercaseString.stringByReplacingOccurrencesOfString(" ",withString: "")

反转:
String(str.characters.reverse())

排序:
str.characters.sort()

去掉换行符
str = NSString(data: inputData,encoding: NSUTF8StringEncoding)!
str.stringByTrimmingCharactersInSet(NSCharacterSet.newlineCharacterSet())

扩展
命名StringExtension.swift
语法extension String{ func methodA() {}}

比较==
比较字符串相等,
"hello" == "hello"
比较数组相等
["hello","world"] == ["hello","world"]

标准输入STDIN

@H_404_49@ func getInput() -> String { // 使用OC的API //1 let keyboard = NSFileHandle.fileHandleWithStandardInput() //2 let inputData = keyboard.availableData //3 let strData = NSString(data: inputData,encoding: NSUTF8StringEncoding)! //4 return strData.stringByTrimmingCharactersInSet(NSCharacterSet.newlineCharacterSet()) // 或者使用swift中新的API //return readLine()! }

标准及错误输出STDOUT,STDERR

@H_404_49@ func writeMessage(message: String,to: OutputType = .Standard) { switch to { case .Standard: print("\u{001B}[;m\(message)") case .Error: fputs("\u{001B}[0;31m\(message)\n",stderr) } }

定义enum

@H_404_49@ enum OutputType { case Error case Standard } enum OptionType: String { case Palindrome = "p" case Anagram = "a" case Help = "h" case Quit = "q" case Unknown init(value: String) { switch value { case "a": self = .Anagram case "p": self = .Palindrome case "h": self = .Help case "q": self = .Quit default: self = .Unknown } } }