<?php

//打开,追加方式

$fp = fopen("demo.txt", "a");

rewind($fp);

echo ftell($fp)."<br>";

//默认在文件末尾追加

fwrite($fp, "hello world\n");

//关闭

fclose($fp);

//打开

$fp = fopen("demo.txt", "r");

echo ftell($fp)."<br>";

fseek($fp, 4);//将指针向后移动4个位置

echo ftell($fp)."<br>";//返回当前指针位置

echo fread($fp, 11)."<br>";

echo ftell($fp)."<br>";

fseek($fp, -3, SEEK_END);//从最后往前移动3个字节,换行也是一个字节

echo fread($fp, 3);

rewind($fp);//直接将文件指针指向开头

echo ftell($fp)."<br>";

//关闭

fclose($fp);

//打开

$fp = fopen("demo.txt", "r");

while(!feof($fp)) {

//读取文件,一次读取n个字符

echo fread($fp, 1024);

}

//关闭

fclose($fp);

//打开

$fp = fopen("demo.txt", "r");

//如果文件出错或者到文件结尾返回真

while(!feof($fp)){

//读取文件，一次读一个字符

echo fgetc($fp);

}

//关闭

fclose($fp);

//打开

$fp = fopen("demo.txt", "r");

while(!feof($fp)) {

//读取文件，一次读一行

echo fgets($fp)."<br>";

}

//关闭

fclose($fp);