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3 min readMar 3, 2026
Swift

How to Read and Write Files

Write a text file to the documents directory.

Steps

  1. Paste the code into a Swift file or playground.
  2. Run it once to verify the output.
  3. Adjust the inputs to match your use case.

Copy and paste

import Foundation

let fileName = "notes.txt"
let text = "Hello, file system!"

let url = FileManager.default.urls(for: .documentDirectory, in: .userDomainMask)[0]
    .appendingPathComponent(fileName)

try text.write(to: url, atomically: true, encoding: .utf8)
let loaded = try String(contentsOf: url)
print(loaded)

Notes

  • Keep functions small and focused for reuse.
  • Prefer safe APIs like optionals and guards.