Page 335 - Beginning PHP 5.3

11

Working with Files and

Directories

As a server - side programming language, PHP allows you to work with files and directories stored
on the Web server. This is very useful, because it means your PHP scripts can store information
outside the scripts themselves.

Files are stored in directories on a hard drive, and because they retain their data after the computer
is shut down, they are a persistent storage mechanism, instead of temporary storage such as RAM.
Directories are a special kind of file made for storing other files. Directories are created
hierarchically inside other directories, starting with the root (top - level) directory and proceeding
down from there.

Files can contain any kind of data, and also can contain quite a bit of information about
themselves, such as who owns them and when they were created. PHP makes working with the
file system easy by including functions that allow you to obtain information about files, as well as
open, read from, and write to them.

This chapter is all about the PHP functions for working with the file system. You learn:
❑ More about files and directories, and how to find out more information about them in
your scripts
❑ How to open and close files, as well as how to read data from, and write data to, files
❑ The concept of file permissions and how to work with them
❑ How to copy, move, and delete files
❑ All about working with directories, including reading their contents, creating them, and
deleting them

As well as learning the theory of file and directory handling, you get to write a script that can
move through a directory tree, listing all the files and directories it finds as it goes. You also create
a simple Web - based text editor to illustrate many of the points covered in the chapter.

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