Practical Common Lisp

CHAPTER 14Files and File I/O

Common Lisp provides a rich library of functionality for dealing with files. In this chapter I'll focus on a few basic file-related tasks: reading and writing files and listing files in the file system. For these basic tasks, Common Lisp's I/O facilities are similar to those in other languages. Common Lisp provides a stream abstraction for reading and writing data and an abstraction, called pathnames, for manipulating filenames in an operating system–independent way. Additionally, Common Lisp provides other bits of functionality unique to Lisp such as the ability to read and write s-expressions.

Reading File Data

The most basic file I/O task is to read the contents of a file. You obtain a stream from which you can ...