PHP file_exists Function

last modified April 3, 2025

The PHP file_exists function checks whether a file or directory exists. It’s essential for file operations to avoid errors when accessing nonexistent files.

Basic Definition

The file_exists function checks if a file or directory exists at the specified path. It returns true if the file/directory exists, false otherwise.

Syntax: file_exists(string $filename): bool. The function works with both files and directories, and accepts relative and absolute paths.

Basic file_exists Example

This shows the simplest usage of file_exists to check a file.

basic_file_exists.php

<?php

declare(strict_types=1);

$file = “example.txt”;

if (file_exists($file)) { echo “The file $file exists”; } else { echo “The file $file does not exist”; }

This checks if “example.txt” exists in the current directory. The function returns a boolean that we use in a conditional statement.

Checking Absolute Path

file_exists works with absolute paths to specific locations.

absolute_path.php

<?php

declare(strict_types=1);

$file = “/var/www/html/config.ini”;

if (file_exists($file)) { echo “Configuration file found”; } else { echo “Configuration file missing”; }

Here we check for a file at an absolute path. This is useful when you need to verify system files or files at specific locations.

Checking Directory Existence

The function can also check if a directory exists, not just files.

directory_check.php

<?php

declare(strict_types=1);

$dir = “uploads”;

if (file_exists($dir) && is_dir($dir)) { echo “The directory $dir exists”; } else { echo “The directory $dir does not exist”; }

We combine file_exists with is_dir to specifically check for directories. This ensures we’re checking a directory, not a file.

URL Check Example

file_exists doesn’t work with HTTP URLs - it’s for local files only.

url_check.php

<?php

declare(strict_types=1);

$url = “https://example.com/image.jpg";

if (file_exists($url)) { echo “This will never be true for HTTP URLs”; } else { echo “Use file_get_contents or cURL for remote files”; }

This demonstrates that file_exists only works with local filesystem paths. For URLs, you need different functions like file_get_contents.

Permission Considerations

File permissions can affect file_exists results.

permissions_check.php

<?php

declare(strict_types=1);

$restricted = “/etc/shadow”;

if (file_exists($restricted)) { echo “File exists but you may not have access”; } else { echo “File may exist but is inaccessible”; }

Even if a file exists, PHP might not have permission to access it. The function may return false for files the web server user can’t read.

Best Practices

• Combine Checks: Use with is_file/is_dir for specific checks.

• Error Handling: Implement proper error handling around file ops.

• Security: Validate and sanitize file paths before checking.

• Caching: Be aware PHP may cache file_exists results.

• Performance: Avoid excessive checks in loops.

Source

PHP file_exists Documentation

This tutorial covered the PHP file_exists function with practical examples showing its usage for checking file and directory existence.

Author

My name is Jan Bodnar, and I am a passionate programmer with extensive programming experience. I have been writing programming articles since 2007. To date, I have authored over 1,400 articles and 8 e-books. I possess more than ten years of experience in teaching programming.

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