Running Bash Script in Swift

Using the script

var address=runScript("ifconfig en0 | grep ether")

utils/runScript.swift

import Foundation

let process=Process()
let pipe=Pipe()

func runScript(_ script: String) -> String {
    process.standardInput=nil //no stdin needed
    process.standardOutput=pipe //output both stdout and stderr to the pipe
    process.standardError=pipe
    process.arguments=["-c", script] //runs bash -c [script]. -c means execute the following argument
    process.executableURL=URL(fileURLWithPath: "/bin/bash")
    
    do {
        if #available(macOS 13.0, *) {
            try process.run() //throws errors
        } else {
            process.launch() //old way
        }
        let data=pipe.fileHandleForReading.readDataToEndOfFile()
        let output=String(data: data, encoding: .utf8) ?? ""
        return output
    } catch {
        print("Running a script resulted in the following error:")
        print(error)
    }
    
    return "Failed to run script"
}

utils/runScript.swift if you want to use sudo in your commands

runScript("sudo ifconfig en0 ether 69:69:69:69:69:69", sudo: true)

func runScript(_ script: String, sudo: Bool=false) -> String {
    let process=Process()
    let pipe=Pipe()
    process.standardInput=nil //no stdin needed
    process.standardOutput=pipe //output both stdout and stderr to the pipe
    process.standardError=pipe
    process.executableURL=URL(fileURLWithPath: "/bin/sh")

    process.arguments=["-c", script] //runs bash -c [script]. -c means execute the following argument
    
    do {
        if #available(macOS 13.0, *) {
            try process.run() //throws errors
        } else {
            process.launch() //old way
        }
        if sudo {
            tcsetpgrp(STDIN_FILENO, process.processIdentifier) //for sudo
        }
        
        let data=pipe.fileHandleForReading.readDataToEndOfFile()
        let output=String(data: data, encoding: .utf8) ?? ""
        return output
    } catch {
        print("Running a script resulted in the following error:")
        print(error)
    }
    
    return "Failed to run script"
}