Using PHP file_exists() to Check File and Directory Existence

In PHP programming, the file_exists() function is used to determine whether a specified file or directory exists.

Syntax: bool file_exists ( string $filename ) Parameter: $filename: the path of the file or directory to check.

Return value: Returns true if the file or directory exists, otherwise false.

Example: The following code demonstrates checking a file and a directory.

<?php
// Check if file exists
$file = 'example.txt';
if (file_exists($file)) {
    echo "文件存在。";
} else {
    echo "文件不存在。";
}

// Check if directory exists
$dir = 'example_dir';
if (file_exists($dir) && is_dir($dir)) {
    echo "目录存在。";
} else {
    echo "目录不存在。";
}
?>

The example first defines a file path variable $file and uses file_exists() to verify its existence, outputting a message accordingly. It then defines a directory path variable $dir and checks both existence and that it is a directory using file_exists() together with is_dir().

Notes:

The function can check local files/directories as well as remote URLs.

It does not differentiate between files and directories; a directory will also return true.

It only reports existence and does not impose access restrictions.

It is advisable to use is_readable() or is_writable() before accessing the file to avoid permission errors.

Summary: file_exists() is an essential PHP function for verifying the presence of files or directories, returning a boolean result that can be combined with other file‑handling functions to build robust file‑system logic.