How can I remove the last line of a file using php?

I created a function to remove x number of lines from the bottom. Set $max to the number of lines you want to delete.

function trim_lines($path, $max) { 
  // Read the lines into an array
  $lines = file($path);
  // Setup counter for loop
  $counter = 0;
  while($counter < $max) {
    // array_pop removes the last element from an array
    array_pop($lines);
    // Increment the counter
    $counter++;
  }  // End loop
  // Write the trimmed lines to the file
  file_put_contents($path, implode('', $lines));
}

Call the function like this:

trim_lines("filename.txt", 1);

The variable $path can be a path to the file or a filename.

This should works :

<?php 

// load the data and delete the line from the array 
$lines = file('filename.txt'); 
$last = sizeof($lines) - 1 ; 
unset($lines[$last]); 

// write the new data to the file 
$fp = fopen('filename.txt', 'w'); 
fwrite($fp, implode('', $lines)); 
fclose($fp); 

?>