如何从文件开头删除 ? [英] How do I remove  from the beginning of a file?

问题描述

我有一个 CSS 文件，当我使用 gedit 打开它时看起来不错，但是当它由 PHP 读取(将所有 CSS 文件合并为一个)，此 CSS 具有以下字符:

I have a CSS file that looks fine when I open it using gedit, but when it's read by PHP (to merge all the CSS files into one), this CSS has the following characters prepended to it: 

PHP 删除了所有空格，因此代码中间的随机  会弄乱整个内容.正如我提到的，当我在 gedit 中打开文件时，我实际上看不到这些字符，所以我不能很容易地删除它们.

PHP removes all whitespace, so a random  in the middle of the code messes up the entire thing. As I mentioned, I can't actually see these characters when I open the file in gedit, so I can't remove them very easily.

我用谷歌搜索了这个问题，文件编码显然有问题，这是有道理的，因为我一直在通过 ftp 和 rsync，带有一系列文本编辑器.不过，我对字符编码不太了解，因此不胜感激.

I googled the problem, and there is clearly something wrong with the file encoding, which makes sense being as I've been shifting the files around to different Linux/Windows servers via ftp and rsync, with a range of text editors. I don't really know much about character encoding though, so help would be appreciated.

如果有帮助，文件正在以 UTF-8 格式保存，gedit 不会让我以 ISO-8859-15 格式保存它(文档包含一个或多个无法使用指定字符编码的字符)编码).我尝试使用 Windows 和 Linux 行结尾保存它，但都没有帮助.

If it helps, the file is being saved in UTF-8 format, and gedit won't let me save it in ISO-8859-15 format (the document contains one or more characters that cannot be encoded using the specified character encoding). I tried saving it with Windows and Linux line endings, but neither helped.

推荐答案

给你三个字:

字节顺序标记 (BOM)

这是 ISO-8859-1 中 UTF-8 BOM 的表示.您必须告诉您的编辑不要使用 BOM 或使用不同的编辑器将它们删除.

That's the representation for the UTF-8 BOM in ISO-8859-1. You have to tell your editor to not use BOMs or use a different editor to strip them out.

要自动移除 BOM，您可以使用 awk，如 这个问题.

To automatize the BOM's removal you can use awk as shown in this question.

作为 另一个答案说，最好让 PHP 正确解释 BOM，为此您可以使用 mb_internal_encoding()，像这样:

As another answer says, the best would be for PHP to actually interpret the BOM correctly, for that you can use mb_internal_encoding(), like this:

 <?php
   //Storing the previous encoding in case you have some other piece 
   //of code sensitive to encoding and counting on the default value.      
   $previous_encoding = mb_internal_encoding();

   //Set the encoding to UTF-8, so when reading files it ignores the BOM       
   mb_internal_encoding('UTF-8');

   //Process the CSS files...

   //Finally, return to the previous encoding
   mb_internal_encoding($previous_encoding);

   //Rest of the code...
  ?>

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