Demo using async-await to read from a FileHandle

FileHandle_async-await.swift

import Foundation

let outputPipe = Pipe()

let process = Process()
process.executableURL = URL(fileURLWithPath:"/bin/bash")
process.arguments = ["-c", "ls"]
process.standardOutput = outputPipe

try? process.run()

for try await line in outputPipe.fileHandleForReading.bytes.lines {
    print(line)
}

let standardInputFH = process.standardInput as! FileHandle
let standardErrorFH = process.standardError as! FileHandle

print("PID: \(process.processIdentifier)")
print("stdin FD: \(standardInputFH.fileDescriptor)")
print("stdout FD: \(outputPipe.fileHandleForReading.fileDescriptor)")
print("stderr FD: \(standardErrorFH.fileDescriptor)")