php 用php清空文件
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Emptying a file with php
提问by Chris Mccabe
Possible Duplicate:
PHP: Is there a command that can delete the contents of a file without opening it?
How do you empty a .txt file on a server with a php command?
如何使用 php 命令清空服务器上的 .txt 文件？
回答by Artefacto
Here's a way to only emptying if it already exists and that doesn't have the problem of using file_exists, as the the file may cease to exist between the file_existscall and the fopencall.
这是一种仅在它已经存在并且没有使用问题的情况下才清空的方法file_exists，因为文件可能在file_exists调用和fopen调用之间不存在。
$f = @fopen("filename.txt", "r+");
if ($f !== false) {
ftruncate($f, 0);
fclose($f);
}
回答by Dan Grossman
Write an empty string as the content of filename.txt:
写一个空字符串作为 的内容filename.txt：
file_put_contents('filename.txt', '');
回答by riha
$fh = fopen('filename.txt','w'); // Open and truncate the file
fclose($fh);
Or in one line and without storing the (temporary) file handle:
或者在一行中并且不存储（临时）文件句柄：
fclose(fopen('filename.txt','w'));
As others have stated, this creates the file in case it doesn't exist.
正如其他人所说，这会创建文件，以防它不存在。
回答by Ferdinand Beyer
Just open it for writing:
只需打开它进行写作：
if (file_exists($path)) { // Make sure we don't create the file
$fp = fopen($path, 'w'); // Sets the file size to zero bytes
fclose($fp);
}
回答by BlueDog
First delete it using unlink()and then just create a new empty file with the same name.
首先使用删除它unlink()，然后创建一个具有相同名称的新空文件。
回答by álvaro González
With ftruncate(): http://php.net/ftruncate
与ftruncate()：http: //php.net/ftruncate
回答by Ankur
you can use the following code
您可以使用以下代码
`
`
$myFile = "testFile.txt";
$fh = fopen($myFile, 'w') or die("can't open file");
$stringData = "";
fwrite($fh, $stringData);
fclose($fh);
` It will just override your file content to blank
` 它只会将您的文件内容覆盖为空白
