We can write to a file by using fwrite() function PHP. Please note that we have to open the file in write mode and if write permission is there then only we can open it in write mode. If the file does not exist then one new file will be created. We can change the permission of the file also. However we can check the presence of a file by using file_exists function. You can read the content of a file by using fopen() function in PHP. This is the way to write entries to a guestbook, counter and many other scripts if you are not using any database for storing data. . Here we will see how to write to a file.
<?Php $body_content="This is my content"; //Store some text to enter inside the file
$file_name="test_file.txt"// file name
$fp = fopen ($file_name, "w");// Open the file in write mode, if file does not exist then it will be created.
fwrite ($fp,$body_content);// entering data to the file
fclose($fp);// closing the file pointer
chmod($file_name,0777);// changing the file permission.
$filename=$_GET['file_name']; // To get the file name from URL
//$filename='test.php'; // file name is stored
$fd = fopen ($filename, "r"); // opening the file in read mode
$contents = fread ($fd, filesize($filename)); // reading the content of the file
fclose ($fd); // closing the file pointer
$fd = fopen ($filename, "w"); // opening the file in write mode
//echo $contents; // printing the file content of the file
fwrite ($fd,$contents); // entering data to the file
chmod($filename,0777); // Setting the write permission
/// Opening the file in a new window and closing again /////