Text Processing with Ruby

Opening a File

Before we can do something with a file, we need to open it. This signals our intent to read from or write to the file, allowing Ruby to do the low-level that make that intention actually happen on the filesystem. Once it’s done those things, Ruby gives us a File object that we can use to manipulate the file.

Once we have this File object, we can do all sorts of things with it: read from the file, write to it, inspect its permissions, find out its path on the filesystem, check when it was last modified, and much more.

To open a file in Ruby, we use the open method of the File class, telling it the path to the file we’d like to open. We pass a block to the open method, in which we can do whatever we like with the file. Here’s an ...