PHP Path and File Operations: Absolute/Relative Paths, Pathinfo, and Directory Functions

This guide introduces the concepts of absolute and relative paths in PHP, showing how an absolute path starts from the drive letter (e.g., D:\Google\123\1.png) and a relative path is based on the current file's directory (e.g., ./1.txt or ../2.txt).

It then demonstrates the pathinfo() function, which returns an associative array containing dirname, basename, extension, and filename for a given path:

<?php
$xianyu = "/love/xianyu.php";
$result = pathinfo($xianyu);
foreach ($result as $key => $value) {
    echo "$key=>$value
";
}
?>
/*
dirname=>/love
basename=>xianyu.php
extension=>php
filename=>xianyu
*/

For quick retrieval of just the filename, basename() can be used:

<?php
$xianyu = "/love/xianyu.php";
echo "Filename is: " . basename($xianyu);
?>
/* Output: Filename is: xianyu.php */

Similarly, dirname() returns the directory part of a path:

<?php
$filepath = "/love/xianyu.php";
echo "Directory part is: " . dirname($filepath);
?>
/* Output: Directory part is: /love */

Directory handling functions are covered next. opendir() opens a directory and returns a handle, which must be closed with closedir():

<?php
$dir = "images";
if ($dir_handle = opendir($dir)) {
    echo "Directory handle obtained!";
    closedir($dir_handle); // release handle
} else {
    echo "Failed to open directory";
}
?>

Creating and deleting directories use mkdir() and rmdir() respectively:

<?php
mkdir("123");
?>

<?php
rmdir("123");
?>

Current working directory can be obtained with getcwd() and changed with chdir():

<?php
echo getcwd() . "<br>";
chdir('hhh');
echo getcwd() . "<br>";
?>

Reading directory entries can be done with readdir() (one entry per call) or scandir() (returns an array of entries, optionally sorted):

<?php
if ($handle = opendir('.')) {
    while (false !== ($file = readdir($handle))) {
        echo "$file
";
    }
    closedir($handle);
}
?>

<?php
$dir1 = scandir("D:\\NewFolder");
$dir2 = scandir("D:\\NewFolder", 1); // descending order
print_r($dir1);
print_r($dir2);
?>

File operations start with checking existence using file_exists():

<?php
if (file_exists("test.txt")) {
    // perform actions
}
?>

Opening, reading, and closing files can be performed with fopen(), fread(), and fclose(), or more simply with file_get_contents():

<?php
$filename = "test.txt";
$handle = fopen($filename, "r");
$contents = fread($handle, filesize($filename));
fclose($handle);
// simpler
$contents = file_get_contents($filename);
?>

Writing to files uses fwrite() or file_put_contents():

<?php
$handle = fopen("test.txt", "w");
fwrite($handle, "Add text to file");
fclose($handle);
// simpler
file_put_contents("test.txt", "Content written with file_put_contents()");
?>

Additional file management functions include unlink() to delete a file, copy() to duplicate a file, and rename() to move or rename files or directories:

<?php
unlink("temp.txt");
?>

<?php
copy("html/cache.txt", "html/copyCache.txt");
?>

<?php
rename('test.txt', 'rename.txt'); // rename file
rename('test', 'rename'); // rename directory
rename('test.txt', 'test/a.txt'); // move and rename file
rename('test', 'html/test'); // move directory
?>

Overall, the article provides a comprehensive reference for handling paths, extracting path components, and performing common directory and file operations in PHP.