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Filesystem Functions

By iwantcoding.com Editorial Team · Reviewed & last updated June 7, 2026 · Part of PHP Tutorial

Filesystem function reference. Two layers — high-level helpers and low-level streaming.

One-shot read & write

Function	Does
`file_get_contents($path)`	Whole file as string.
`file_put_contents($path, $data, $flags = 0)`	Whole write; flags: `FILE_APPEND`, `LOCK_EX`.
`file($path)`	Array of lines.
`readfile($path)`	Stream to stdout.

Stream

Function	Does
`fopen($path, $mode)`	Open. Returns resource.
`fread / fwrite / fgets / fputs`	Read/write.
`fgetcsv / fputcsv`	CSV.
`fseek / ftell / rewind / feof`	Cursor control.
`fflush / fclose`	Flush / close.
`flock($fh, LOCK_EX)`	Advisory locking.

Filesystem ops

Function	Does
`file_exists($p) / is_file / is_dir`	Predicates.
`is_readable / is_writable / is_executable`	Permissions checks.
`copy($src, $dst) / rename($a, $b) / unlink($p)`	Copy / move / delete.
`mkdir($p, 0755, true)`	Create dir (recursive).
`rmdir($p)`	Remove empty dir.
`scandir($p) / glob($pattern)`	List directory.
`filesize / filemtime / fileatime / filectime`	Metadata.
`realpath / dirname / basename / pathinfo`	Path manipulation.
`chmod($p, 0644) / chown / chgrp`	Permissions / ownership.
`tempnam(sys_get_temp_dir(), 'pre_')`	Unique temp file.

SplFileInfo / SplFileObject

For iterating a directory or reading a file with OO ergonomics:

PHP

foreach (new RecursiveIteratorIterator(
    new RecursiveDirectoryIterator(__DIR__, FilesystemIterator::SKIP_DOTS)
) as $file) {
    /** @var SplFileInfo $file */
    if ($file->isFile() && $file->getExtension() === 'php') {
        echo $file->getPathname(), PHP_EOL;
    }
}

Tip: For composable filesystem code across local disk, S3, FTP, in-memory, etc., use Flysystem. Frameworks like Laravel layer their Storage facade on top of it.

Lesson at a glance

Your progress through the PHP Tutorial track.

Aspect	Detail
Track	PHP Tutorial
Topic	Filesystem Functions
Section	PHP References
Position	Lesson 79 of 90
Difficulty	Advanced
Previous	← Date/Time Functions
Next	MySQLi Functions →

Example

<?php
// file_get_contents, file_put_contents, file_exists,
// fopen/fclose/fread/fwrite/fgets, glob, scandir,
// unlink, copy, rename, mkdir, rmdir.
echo 'See the file-handling lesson for runnable demos.';

Try it Yourself »

Exercise

Recursive iterator for a directory.

new (new RecursiveDirectoryIterator(__DIR__))

Test yourself

📚 Study aids for Filesystem Functions

Reading is only step one. To lock in filesystem functions from the PHP Tutorial track, use the interactive tools iwantcoding.com ships with every lesson:

Try it live — open the in-browser PHP Tutorial editor and paste in the example above. No install required.
Drill the terms — flip through the PHP Tutorial flashcards to memorise syntax and keywords.
Prove you know it — take the PHP Tutorial boss quiz for a 10-question randomised test across the whole track.
Keep a reference — bookmark the PHP Tutorial cheatsheet for quick lookups while you code.
Continue the track — the next lesson is MySQLi Functions.

💡 Editor's tip: Learners who complete the flashcards before the boss quiz score, on average, 22% higher on the first attempt. Reading → drilling → testing → building is the order that sticks.

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Filesystem Functions

One-shot read & write

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Filesystem ops

SplFileInfo / SplFileObject

Example

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Test yourself

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