How do I read read from and write to a text file?

WIll “System.IO” also work on a Mac?

If somebody could explain exactly how this works, thanks

public TextAsset asset; // Assign that variable through inspector
private string assetText;

void Start() {
  assetText = asset.Text; // The assetText variable contains the text
                          // If you're looking to extract data from that,
                          // I would say go with XML. Otherwise, use the 
                          // System.Regex class
}

Writing to the text file is quite a bit more difficult. However, here is another method that requires a bit of setup and isn’t exactly good practice…make sure to add using UnityEngine at the top. The text file you’re reading/writing from needs to go into a special directory called "Resources".

public string FileName; // This contains the name of the file. Don't add the ".txt"
                        // Assign in inspector
private TextAsset asset; // Gets assigned through code. Reads the file.
private StreamWriter writer; // This is the writer that writes to the file

void AppendString(string appendString) {
  asset = Resources.Load(FileName + ".txt") as TextAsset;
  writer = new StreamWriter("Resources/" + FileName + ".txt"); // Does this work?
  writer.WriteLine(appendString);
}

In Update() use the AppendString() function to write text.

Yes, System.IO works on Mac

http://forum.unity3d.com/threads/5084-Can-I-read-and-write-text-files-using-Javascript