Appending multiple entries to an output file with a crontab using php? - php

Question

I am writing a script in PHP in which I had to write the system uptime, the current time, and the amount of users logged in the system into a log file, and be updated continually via a crontab.
What I need help with is that I would like the updates to accumulate within the file and be added continually. So far, whenever my script gets executed, the newest update overwrites the previous update.
What I've done is that I tried to declare an array of entries and as I iterate through the array push the contents of the update into the array (It might be a bit of half-baked logic on my part).
My Code:
$fileName = '../so-and-so directory/output.log';
$dt = date('m/d/y');
$time = date('h:i A');
$data = shell_exec('uptime');
$uptime= explode(' up ', $data);
$uptime = explode(', ', $uptime[1]);
$uptime = $uptime[0].','.$uptime[1];
$users = system('w', $who);
$array = new SplFixedArray(3);
$fileLog = fopen($fileName, 'w');
$fileString = "Date: ".$dt. "\n". " Time: ".$time . "\n".
"System uptime ". $uptime ."\n" ."Users " . $users;
foreach ($array as $entry) {
array_push(file_put_contents($fileName, $fileString));
}
fclose($fileLog);
I feel that the solution is very simple but I'm missing it. Would somebody please clue me in?

Answer 1

The "w" filemode truncates the file on open. "a" appends to the end instead. See fopen(3) or the PHP documentation for details.
Also, file_put_contents() is destroying the file. Try fwrite() instead.

Answer 2

drop fopen; simply use
file_put_contents($fileName, $fileString);
file_put_contents will overwrite the existing file by default.
In short:
$fileName = '../so-and-so directory/output.log';
$dt = date('m/d/y');
$time = date('h:i A');
$data = shell_exec('uptime');
$uptime= explode(' up ', $data);
$uptime = explode(', ', $uptime[1]);
$uptime = $uptime[0].','.$uptime[1];
$users = system('w', $who);
$fileString = "Date: ".$dt. "\n". " Time: ".$time . "\n".
"System uptime ". $uptime ."\n" ."Users " . $users;
file_put_contents($fileName, $fileString);

Answer 3

So it turns out that I needed to edit my crontab file as such:
* * * * * such-and-such-script.php >> ../so-and-so directory/output.log 2>&1
To make them append without the previous one being overwritten by the new one. I also lost the fopen() and instead of doing file_put_contents, I did fwrite() into the file. It works great now. Thank you!