How to apply code on multiple files at once? - php

Question

I couldn't find a solution to this. I'm sorry if this is a silly question.
I have 4 log files and I need to remove all log except last 10 lines.
I'm able to do it for 1 file but how to apply it on 4 files using once simple php code?
My current code:
<?php
$lines_array = file("log.txt");
$lines = count($lines_array);
$new_output = "";
for ($i=$lines - 10; $i < $lines; $i++) {
$new_output .= $lines_array[$i];
}
$filename = "log.txt";
file_put_contents($filename,$new_output);
What is the best way to achieve this?

Answer 1

Functional programming to the rescue:
function rotate(string $filename)
{
$lines_array = file($filename);
$lines = count($lines_array);
$new_output = "";
for ($i=$lines - 10; $i < $lines; $i++) {
$new_output .= $lines_array[$i];
}
file_put_contents($filename,$new_output);
}
rotate('log1.txt');
rotate('someOtherLog.txt');
rotate('third/log/file.txt);
//etc.
// or,
$logs = [
'log1.txt',
'someOtherLog.txt',
'third/log/file.txt'
];
foreach($logs as $file) {
rotate($file);
}
This allows you to write the code for rotating your logs one time, which makes your code better by being DRY (Don’t Repeat Yourself)

Answer 2

List your logfiles in an array, and loop over it, rewriting the log files as you go:
$logs = [
'log1.txt',
'log2.txt',
'log3.log'
];
foreach($logs as $log) {
// Only do this if we read the file.
if ($logData = file($log)) {
// array_slice takes a portion of the array
file_put_contents($log, array_slice($logData,-10));
}
}

Answer 3

Please try this code:
<?php
$fp = fopen("log.txt","ab+");
$data = fread($fp,filesize("log.txt"));
$data_array = explode("\n",$data);
$new_data = array();
for($i = count($data_array) - 1; $i >= count($data_array) - 10;$i--)
{
array_push($new_data , $data_array[$i]);
}
fclose($fp);
$new_data_array = array_reverse($new_data);
$data = implode("\n",$new_data_array);
$fp = fopen("log.txt","w");
fwrite($fp,$data);
fclose($fp);
?>