File handling in PHP

Reading data

To simply get the contents of a file and store it as a string, use the file_get_contents function.

echo file_get_contents('hello.txt');

This code will simply output the contents of the file. Alternatively you can get the contents of a file line by line in an array using the file function.

foreach(file('hello.txt') as $text)
   echo $text.'<br />';

The lines of the file are returned as an array and this code outputs each line.

Writing data

To write data to a file you have to open the file, and then use the fwrite function to write data to the file. The fopen function accepts two arguments, a file pointer and a method of opening the file, the various methods are outlined below.

Parameter	code
Read only from beginning of file	r
Read and write from beginning of file	r+
Write only (overwrite)*	w
Read and write (overwrite)*	w+
Write only (append)*	a
Read and write (append)*	a+
Create and open a file for writing (if the file exists false will be returned)*	x
Create and open a file for reading and writing (if the file exists false will be returned)*	x+

* If the file does not exist then one will be created.

$open = fopen('hello.txt','w+');
$text = 'Hello';
fwrite($open, $text);
fclose($open);

This example opens a file and overwrites the contents with a string. An alternative is to use file_put_contents.

file_put_contents('hello.txt', 'my string');

This writes the data to the file specified (and creates the file if it does not exist). This function automatically overwrites data but can be set to append data.

file_put_contents('hello.txt', 'my string', FILE_APPEND);

File functions

PHP has a variety of methods for working with files. The examples below demonstrate simple uses of them.

filesize($file);
filetype($file);

These functions return the size of the file specified and the type of the file (dir, file etc).

is_readable($file);
is_writable($file);
file_exists($file);

These functions check whether a file is readable, writable or exists respectively.

copy($file);
rename($oldFile, $newFile);
unlink($file);

This set of functions can copy a file, rename a file or delete a file respectively.