Execute shell commands in Swift from String or Array

shell.swift

import Foundation

public extension Array where Element == String {
    @discardableResult
    func exec() -> String {
        joined(separator: " ").exec()
    }
}

public extension String {
    static var alphabet = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789"

    @discardableResult
    func exec() -> String {
        let task = Process()
        task.launchPath = "/bin/bash"
        task.arguments = ["-c", self]

        let pipe = Pipe()
        task.standardOutput = pipe
        task.launch()

        let data = pipe.fileHandleForReading.readDataToEndOfFile()
        let output = NSString(data: data, encoding: String.Encoding.utf8.rawValue)! as String

        return output
    }

    static func random(length: Int = 20) -> String {
        var randomString = ""

        for _ in 0 ..< length {
            let randomValue = Int.random(in: 0 ..< String.alphabet.count)
            randomString += "\(String.alphabet[String.alphabet.index(String.alphabet.startIndex, offsetBy: randomValue)])"
        }

        return randomString
    }
}