php打开文件失败

1、在linux环境下用PHP脚本fopen打开文件“t1.txt”，路径写成“/test/t1.txt”时出错
Warning: fopen(/test/t1.txt) [function.fopen]: failed to open stream: No such file or directory
in /var/www/test/5-3.php on line 24
Unable to open file!

原始代码如下：
$file = fopen("/test/t1.txt", "r") or exit("Unable to open file!");

//Output a line of the file until the end is reached

while(!feof($file))

{

echo fgets($file). "<br />";

}

fclose($file);

2、解决方法
我查了一些资料发现是路径不完整造成的，写成 /var/www/test/t1.txt 就可以了。
修改后的代码：
$file = fopen("/var/www/test/t1.txt", "r") or exit("Unable to open file!");

//Output a line of the file until the end is reached

while(!feof($file))

{

echo fgets($file). "<br />";

}

fclose($file);