Running/launching an existing executable program from swift on macOS

Using Swift
1

Hi All, O.K. I'm new to swift and apple. I've worked in C and Tcl/Tk. What I'm trying to do is run an executable on MacOS from swift. Specifically aescrypt. I've played with Process and task.esecutableURL but they all seem to fail. Any hints. Thanks

2

I'm guessing you tried to use the path to your executable for executableURL, while it should be the path to the shell.

Something like this works for me:

import Foundation

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

process.standardOutput = pipe // you can also set stderr and stdin
process.executableURL = URL(fileURLWithPath: "/bin/bash") // or any other shell you like
process.arguments = ["-c", "the command you use to run your executable normally"]

try! process.run()
//	process.waitUntilExit() // you might need this

let data = pipe.fileHandleForReading.readDataToEndOfFile()

guard let standardOutput = String(data: data, encoding: .utf8) else {
	FileHandle.standardError.write(Data("Error in reading standard output data".utf8))
	fatalError() // or exit(EXIT_FAILURE) and equivalent
	// or, you might want to handle it in some other way instead of a crash
}

In addition, you can wrap the whole thing in a function like this:

/// Executes a shell command with `/bin/bash`.
/// - Parameter command: The command to execute.
/// - Returns: The standard output from executing `command`.
@discardableResult
func bash(_ command: String) -> String { ... }

and then call it like this:

bash("the command you use to run your executable normally")
// or
let standardOutput = bash("the command you use to run your executable normally")
1 Like
3

Thank you. I now have it working for what I wanted, and your explanation was the key !

4

// Thanks again wow bagger, you example/suggestion brought me to this code below.
// This is what worked for me to run command aescrypt. put together from several sources
// below now works**

import Foundation

func executeCommand(command: String, args: [String]) -> String {
let task = Process()
task.launchPath = command
task.arguments = args
let pipe = Pipe()

task.standardOutput = pipe
task.launch()

let data = pipe.fileHandleForReading.readDataToEndOfFile()
let output: String = String(decoding: data, as: UTF8.self)
return output
}
let commandOutput = executeCommand(command:"/bin/bash",args: ["-c", "exec /usr/local/bin/aescrypt -k /Users/usr/.secret.key -e /Users/usr/test.swift"])**

5

I have a problem with an executable that asks for permissions ; when I execute it from terminal, the 1st time a window is open and I can script the requested permission, and from then it works regularly ; while, launching in this way, the window is not open, and even if I had previously granted permission via terminal, it gives error anyway (is there a way to request additional privileges when execute shell?)

6

Make sure you are reading the output buffers (standard and errors), else your program call might crash or hang after too much unread output. You might have a look at this function.