How to access file system using PHP built-in functions?

PHP built-in functions can access the file system and perform file operation tasks, such as: creating and opening files (fopen()), reading and writing data (fread(), fwrite()), and managing directories (mkdir(), rmdir (), scandir())

Use PHP built-in functions to access the file system

PHP provides a wealth of built-in functions that can be used for accessing and manipulating file systems. These functions allow you to perform various file manipulation tasks, such as creating and opening files, reading and writing data, and managing directories.

Creating and opening files

You can use the fopen() function to create and open a file. The syntax is as follows:

$file = fopen("path_to_file", "mode");

Among them, path_to_file is the path of the file, and mode specifies the mode in which to open the file. For example, the following code creates and opens a file named test.txt for writing:

$file = fopen("test.txt", "w");

Reading and Writing Data

Once the file is opened, data can be read and written using the fread() and fwrite() functions. The syntax is as follows:

• fread($file, $length): Read $length bytes of data
• fwrite($file, $ data): Write $data string

The following example writes some text to a file:

fwrite($file, "Hello, world!");

Manage directory

PHP also provides some functions to manage directories. For example, you can use the mkdir(), rmdir(), and scandir() functions to create, delete, and list directories. The syntax is as follows:

• mkdir("path_to_directory"): Create a directory
• rmdir("path_to_directory"): Delete a directory (if Empty)
• scandir("path_to_directory"): List the files in the directory

Actual case

Suppose we want to create a simple file management program that allows users to create, edit and delete files. We can use the following code:

<?php
// 创建或打开文件
$file = fopen("test.txt", "a+");

// 读取文件内容
$contents = fread($file, filesize("test.txt"));

// 将新行添加到文件
fwrite($file, "\nNew line");

// 关闭文件
fclose($file);
?>

This code opens the test.txt file and reads its contents. Then it adds a new line and closes the file.

Summary

PHP built-in functions provide powerful functions for accessing and operating file systems. By understanding these functions, you can easily build various file management applications.

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