如何从文件的开头删除 [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 打开时，看起来不错，但是当它由PHP读取（将所有的CSS文件合并为一个），这个CSS有以下的字符前面：

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删除所有的空格，随机的在代码的中间混乱了整个事情。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.

并且文件编码有明显的问题，这是有意义的，因为我一直在通过ftp和 rsync ，包含一系列文本编辑器。我真的不知道很多关于字符编码，所以帮助将不胜感激。

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.

如果它有帮助，文件被保存为UTF-8格式，gedit不会让我将它保存为ISO-8859-15格式（文档包含一个或多个字符，不能使用指定的字符编码进行编码）。

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

三个字给你：

字节顺序标记（BOM）

这是ISO-8859-1中UTF-8 BOM的表示形式。

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.

要自动化BOM的移除，您可以使用 awk ，如此问题所示

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

由于另一个答案说，，最好是PHP真正解释BOM，因为您可以使用 mb_internal_encoding（） ，例如：

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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