Question

I have:

<?php  $file=fopen(date('Y-m-d').'.txt','r+') or exit('Unable to open file!');  if ($_POST['lastname'] <> '') {    fwrite($file,$_POST['lastname'].'\n'); }  fclose($file);  ?> 

but it overwrites the beginning of the file. How do I make it insert?

Answer 1

I’m not entirely sure of your question – do you want to write data and not have it over-write the beginning of an existing file, or write new data to the start of an existing file, keeping the existing content after it?

To insert text without over-writing the beginning of the file, you’ll have to open it for appending (a+ rather than r+)

$file=fopen(date('Y-m-d').'.txt','a+') or exit('Unable to open file!');  if ($_POST['lastname'] <> '') {    fwrite($file,$_POST['lastname'].'\n'); }  fclose($file); 

If you’re trying to write to the start of the file, you’ll have to read in the file contents (see file_get_contents) first, then write your new string followed by file contents to the output file.

$old_content = file_get_contents($file); fwrite($file, $new_content.'\n'.$old_content); 

The above approach will work with small files, but you may run into memory limits trying to read a large file in using file_get_conents. In this case, consider using rewind($file), which sets the file position indicator for handle to the beginning of the file stream. Note when using rewind(), not to open the file with the a (or a+) options, as:

If you have opened the file in append (‘a’ or ‘a+’) mode, any data you write to the file will always be appended, regardless of the file position.