PHP：如何从大文件中删除最后N个字节？

Question

我有一个大文件，需要删除最后512个字节。我不想复制文件。

感谢。

Answer 1

您应该使用ftruncate(handle, file_size - 512)（使用filesize或fstat功能获取文件大小）

Answer 2

fstat，ftruncate，fopen和fclose的使用示例：

<?php    

$bytesToTruncate = 5; // how many bytes we are going to delete from the end of the file

$handle = fopen('/home/francesco/mytest', 'r+'); // Open for reading and writing; place the file pointer at the beginning of the file.

$stat = fstat($handle);
$size = $stat['size'] - $bytesToTruncate;
$size = $size < 0 ? 0 : $size;

ftruncate($handle, $size);
fclose($handle);

• http://www.php.net/manual/en/function.fopen.php
• http://www.php.net/manual/en/function.fstat.php
• http://www.php.net/manual/en/function.ftruncate.php
• http://www.php.net/manual/en/function.fclose.php

Answer 3

我没有用大文件测试它，但你可以尝试一下：

• http://es.php.net/filesize
• http://es.php.net/ftruncate