Delete all lines from a file after the 20th line

[speedy131]

Hi

I'm trying to prune some files because they're getting huge

they're not txt files but .db files, but i guess that doesn't matter as they also just have plain text in them

when new lines get added to those files they go to the top, so the oldest data is at the bottom

now i'd only need the 400 newest lines to stay there, everything after can be deleted.

The tricky part is probably that some files don't have 400 lines in them yet, so nothing needs to be deleted there.

there's over 1700 of these files in a directory, so it would be best if the script does all of them

i guess i can do that with

$dirname = "inc";
$dh = opendir("$dirname") or die("Couldn't do it");
while ( $file = readdir($dh) ) {
if ($file == ".." || $file == ".") continue;

and then open $file each time

can somebody please help me with the deleting after 400th line thing ?

thank you 😉

[drew010]

you can use the [man]file()[/man] function to read the contents into an array, where each line is its own array index. so then you can do something like

if (sizeof($fileArr) > 400)) {
  $fileArr = array_slice($fileArr, 0, 399);
}

$fp = fopen("filename.db", "w+");
foreach ($fileArr as $one) {
  fwrite($fp, $one);
}

[speedy131]

excellent ! that worked 😃

thank you very much drew