Simply execute shell commands from Swift

Executable.swift

public struct Executable {

    let url: URL

    public init(_ filePath: String) {
        url = URL(fileURLWithPath: filePath)
    }

    public init(_ url: URL) {
        self.url = url
    }

    public func callAsFunction(_ arguments: String...) -> (stdout: String, stderr: String) {

        let process = Process()
        process.executableURL = url
        process.arguments = arguments

        let stdout = Pipe()
        process.standardOutput = stdout

        let stderr = Pipe()
        process.standardError = stderr

        process.launch()
        process.waitUntilExit()

        return (
            stdout: stdout.readStringToEndOfFile(),
            stderr: stderr.readStringToEndOfFile()
        )
    }
}

extension Pipe {
    func readStringToEndOfFile(trimming: CharacterSet = .whitespacesAndNewlines) -> String {
        String(decoding: fileHandleForReading.readDataToEndOfFile(), as: UTF8.self).trimmingCharacters(in: trimming)
    }
}