PHP file_put_contents() Function

The PHP file_put_contents() function writes data to a file.

This function is identical to calling fopen(), fwrite() and fclose() successively to write data to a file.

If filename does not exist, the file is created. Otherwise, the existing file is overwritten, unless the FILE_APPEND flag is set.

Syntax

file_put_contents(filename, data, flags, context)

Parameters

`filename`	`Required.` Specify the path to the file where to write the data. If the file does not exist, this function will create one.
`data`	`Required.` Specify the data to write. It can be either a string, an array or a stream resource. If the data is a stream resource, the remaining buffer of that stream will be copied to the specified file. If the data is a single dimension array then it is equivalent to file_put_contents($filename, implode('', $array)).
`flags`	`Optional.` Specify how to open/write to the file. The possible values are: FILE_USE_INCLUDE_PATH - Search for filename in the include directory. include_path can be set in php.ini. FILE_APPEND - If file filename already exists, append the data to the file instead of overwriting it. LOCK_EX - Put an exclusive lock on the file while proceeding to the writing. In other words, a flock() call happens between the fopen() call and the fwrite() call. This is not identical to an fopen() call with mode "x". The value of flags can be any combination of the above mentioned flags, joined with the binary OR (\|) operator.
`context`	`Optional.` Specify a valid context resource created with stream_context_create() function. Context is a set of options that can modify the behavior of a stream.

Return Value

Returns the number of bytes that were written to the file, or false on failure.

Note: This function may return Boolean false, but may also return a non-Boolean value which evaluates to false. Therefore, use === operator for testing the return value of this function.

Example: writing data to a file

Lets assume that we have a file called test.txt. This file contains following content:

This is a test file.
It contains dummy content.

In the example below, file_put_contents() function is used to write some content to it.

<?php
$file = "test.txt";

//displaying the content of the file
echo file_get_contents($file)."\n";

//using file_put_contents() function 
//to write some content to it
file_put_contents($file, "Content is modified now.");

//displaying the content of the file
echo "\n".file_get_contents($file)."\n";
?>

The output of the above code will be:

This is a test file.
It contains dummy content.

Content is modified now.

Example: appending data to a file

By using FILE_APPEND flag, we can append content to the file. Consider the example below:

<?php
$file = "test.txt";

//displaying the content of the file
echo file_get_contents($file)."\n";

//using file_put_contents() function 
//to write some content to it
file_put_contents($file, 
                  PHP_EOL."Third line is appended.",
                  FILE_APPEND);

//displaying the content of the file
echo "\n".file_get_contents($file)."\n";
?>

The output of the above code will be:

This is a test file.
It contains dummy content.

This is a test file.
It contains dummy content.
Third line is appended.

❮ PHP Filesystem Reference