Reading Information About Files

PHP offers a variety of functions that provide information about a file. The following list shows the most relevant functions in this regard:

• fileatime($filename) Last access to the file
• filegroup($filename) Group that owns the file
• filemtime($filename) Last change to the file
• fileowner($filename) File owner
• filesize($filename) Size of the file
• stat($filename) Gives information about a file

fileatime()

<?php
 //Syntax
 fileatime(string $filename): int|false

The fileatime() function returns the time of last access of a file or false on error.

<?php
 $atime = fileatime('file.txt');
 if ($atime !== flase)
  echo 'Last access: '. $atime;
 else
  echo 'Error'; 

// Prints: Last access: 1671484767

The time is returned as a Unix timestamp, use the Date function to convert the timestamp into a human-readable form:

 echo Date('h:i:s, d-M-Y', $atime);
 // Prints: 10:19:27, 19-Dec-2022

filegroup()

<?php
 //Syntax
 filegroup(string $filename): int|false

The filegroup() function returns the group ID of the group owning the file path or false on error.

<?php
 $group = filegroup('file.txt');
 if ($group !== false)
  echo 'group ID: '. $group;
 else
  echo 'Error';

filemtime()

<?php
 //Syntax
 filemtime(string $filename): int|false

The filemtime() function returns a file’s last modification time or false on failure.

<?php
 $mtime = filemtime('file.txt');
 if ($mtime !== false)
  echo $mtime;
 else
  echo 'Error'; 

 //Prints Unix timestamp: 1671484767

Use the Date function to convert the Unix timestamp into human-readable form:

<?php
 echo Date('h:i:s, d-M-Y', $mtime);
 // 10:19:27, 19-Dec-2022

fileowner()

<?php
 //Syntax
 fileowner(string $filename): int|false

The fileowner() function returns the user ID of the owner of a file, or false if an error occurs.

<?php
 $owner = fileowner ('file.txt');
 if ($owner !== false)
  echo 'User ID: '. $owner;
 else
  echo 'Error';

filesize()

<?php
 //Syntax
 filesize(string $filename): int|false

The filesize()function returns a file’s size in bytes.

<?php
 echo filesize ('file.txt'); // 39421
 echo filesize ('/home/htdocs/img.png'); //189399

stat() – read a file’s metadata

<?php
 //Syntax
 stat(string $filename): array|false

You can also use the stat() function to get similar data with a single function call, it returns an array of information about a file:

<?php
 $file = 'file.txt';
 $meta = stat($file);
 echo '<pre>';
 print_r($meta);

//Prints:
Array
(
    [0] => 2065
    [1] => 136068100
    [2] => 33188
    [3] => 1
    [4] => 2371
    [5] => 2366
    [6] => 0
    [7] => 3236
    [8] => 1671812782
    [9] => 1591680310
    [10] => 1670696965
    [11] => 4096
    [12] => 8
    [dev] => 2065
    [ino] => 136068100
    [mode] => 33188
    [nlink] => 1
    [uid] => 2371
    [gid] => 2366
    [rdev] => 0
    [size] => 3236
    [atime] => 1671812782
    [mtime] => 1591680310
    [ctime] => 1670696965
    [blksize] => 4096
    [blocks] => 8
)

The stat() function returns an array with both numeric and string indexes with information about a file. The following values are returned by this function:

Numeric	Associative	Description
0	dev	device number
1	ino	inode number
2	mode	inode protection mode (see file permissions)
3	nlink	number of links
4	uid	userid of owner (return 0 on Windows)
5	gid	groupid of owner (return 0 on Windows)
6	rdev	device type, if inode device
7	size	file size in bytes
8	atime	time of last access (Unix timestamp)
9	mtime	time of last modification (Unix timestamp)
10	ctime	time of last inode change (Unix timestamp)
11	blksize	blocksize of filesystem IO (return -1 on Windows)
12	blocks	number of 512-byte blocks allocated (return -1 on Windows)

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Working with Files in PHP: