如何使用PHP从文本文件的开头删除X行数? [英] How to use PHP to delete X number of lines from the beginning of a text file?

问题描述

我正在编写一个PHP脚本，该脚本会输出一个简单的文本文件日志，记录其执行的操作.当文件达到特定大小时，我将如何使用PHP从该文件中删除前几行?

I'm writing a PHP script and the script outputs a simple text file log of the operations it performs. How would I use PHP to delete the first several lines from this file when it reaches a certain file size?

理想情况下，我希望它保留前两行(创建的日期/时间和空白)，并从第3行开始删除，并删除X行.我已经了解filesize()函数，因此将使用它来检查文件大小.

Ideally, I would like it to keep the first two lines (date/time created and blank) and start deleting from line 3 and delete X amount of lines. I already know about the filesize() function, so I'll be using that to check the file size.

示例日志文本:

*** LOG FILE CREATED ON 2008-10-18 AT 03:06:29 ***

2008-10-18 @ 03:06:29  CREATED: gallery/thumbs
2008-10-18 @ 03:08:03  RENAMED: gallery/IMG_9423.JPG to gallery/IMG_9423.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/IMG_9188.JPG to gallery/IMG_9188.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/IMG_9236.JPG to gallery/IMG_9236.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/IMG_9228.JPG to gallery/IMG_9228.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/IMG_3104.JPG to gallery/IMG_3104.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/First dance02.JPG to gallery/First dance02.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/BandG02.JPG to gallery/BandG02.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/official03.JPG to gallery/official03.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/Wedding32.JPG to gallery/Wedding32.jpg
2008-10-18 @ 03:08:03  RENAMED: gallery/Gettaway car16.JPG to gallery/Gettaway car16.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/Afterparty05.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/IMG_9254.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/IMG_9175.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/official05.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/First dance01.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/Wedding29.jpg
2008-10-18 @ 03:08:04  CREATED: gallery/thumbs/men walking.jpg

推荐答案

$x_amount_of_lines = 30;
$log = 'path/to/log.txt';
if (filesize($log) >= $max_size)) {
  $file = file($log);
  $line = $file[0];
  $file = array_splice($file, 2, $x_amount_of_lines);
  $file = array_splice($file, 0, 0, array($line, "\n")); // put the first line back in
  ...
}

通过rcar进行更正并保存第一行.

edit: with correction from by rcar and saving the first line.

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