At some point, programs will need to work with persistent data. This section explores writing and reading data to and from the hard drive. Lua provides facilities to read and write files through its io library. A file doesn't have to contain textual data; you can store data as a binary representation. Reading and writing binary data with Lua is also possible.
File IO
Opening a file
When writing to a file or reading from a file, that file needs to be opened first. Lua provides the io.open function to open files. On success, the io.open function will return a file handle. On failure, it will return nil:
file = io.open("my_file.txt"); -- Opens existing file in read only mode
The preceding line of code will open...
