string filetype ( string filename ) 

<?php
echo filetype('test/a.txt');  // file
echo filetype('test/');        // dir
echo filetype('test/b.txt');  // Warning: filetype(): Lstat failed for test/b.txt
?>

bool is_dir(_name)

bool is_file(_name)    

<?php
var_dump (is_file('test/a.txt'));  //boolean true
var_dump (is_dir('test/'));        //boolean true
?>

<?php
var_dump (file_exists('test/a.txt'));  //boolean true
var_dump (filesize('test/a.txt'));  // int 0
var_dump (is_readable('test/a.txt'));  //boolean true
var_dump (is_writeable('test/a.txt'));  //boolean true
var_dump (is_executable('test/a.txt'));  //boolean false
var_dump (date("Y-m-d H:i:s",(filectime('test/a.txt'))));//string '2016-11-22 06:47:54' (length=19)
var_dump (date("Y-m-d H:i:s",(filemtime('test/a.txt'))));//string '2016-11-22 06:47:54' (length=19)
var_dump (date("Y-m-d H:i:s",(fileatime('test/a.txt'))));//string '2016-11-22 06:47:54' (length=19)
?>

$unixPath="/var/www/html/index.php";    //在UNIX系统中的绝对路径，必须使用"/"分隔
$winPath="C:\\Appserv\\www\\index.php"; //在Windows系统的绝对路径，默认使用"\"分隔
$winPath2="C:/Appserv/www/index.php";   //在Windows系统中也可使用“/”分隔

<?php
echo "c:".DIRECTORY_SEPARATOR."a".DIRECTORY_SEPARATOR."b".DIRECTORY_SEPARATOR."c"; //c:\a\b\c
?>

<?php
echo "aaa/ccc/ddd".PATH_SEPARATOR."/www/yyyy";//aaa/ccc/ddd;/www/yyyy
?>

<?php
var_dump (file_exists('test/a.txt'));//boolean true
var_dump (file_exists('./test/a.txt'));//boolean true
var_dump (file_exists('../www/test/a.txt'));//boolean true
?>

<?php
echo '<img src="/a.jpg">';//客户端根路径，相当于d:\wamp\www\a.jpg
mkdir('/hello');//服务器根路径，相当于d:\hello
?>

<?php
echo "1) ".basename("/etc/sudoers.d", ".d");//1) sudoers
echo "2) ".basename("/etc/passwd").PHP_EOL;//2) passwd
echo "3) ".basename("/etc/").PHP_EOL;//3) etc
echo "4) ".basename(".").PHP_EOL;//4) .
echo "5) ".basename("/");//5)
?>

<?php
echo "1) " . dirname("/etc/passwd") . PHP_EOL; // 1) /etc
echo "2) " . dirname("/etc/") . PHP_EOL; // 2) \
echo "3) " . dirname("."); // 3) .
?>

<?php
$path_parts = pathinfo('/www/htdocs/inc/lib.inc.php');
echo $path_parts['dirname'], "\n";// '/www/htdocs/inc' 目录名
echo $path_parts['basename'], "\n";// 'lib.inc.php' 文件名
echo $path_parts['extension'], "\n";// 'php' 文件后缀
echo $path_parts['filename'], "\n"; // 'lib.inc' 文件名不带后缀
?>

<?php
echo realpath('/wamp');// 'D:\wamp'
?>

array glob ( string $pattern [, int $flags = 0 ] )

<?php
foreach (glob("*.txt") as $filename) {//a.txt size 1050 b.txt size 73echo "$filename size " . filesize($filename) . "\n";
}
?>

resource opendir ( string $path [, resource $context ] )

<?php
var_dump(opendir('test'))//resource(3, stream)
?>

void closedir ([ resource $dir_handle ] )

<?php
$dir = opendir('test');
closedir($dir);
?>

string readdir ([ resource $dir_handle ] )

<?php
$dir = opendir('test');
echo readdir($dir)."<br>";//.
echo readdir($dir)."<br>";//..
echo readdir($dir)."<br>";//a.txt
echo readdir($dir)."<br>";//b.txt
echo readdir($dir)."<br>";//
closedir($dir);
?>

<?php
if ($handle = opendir('test')) {while (false !== ($file = readdir($handle))) {if ($file != "." && $file != "..") {echo "$file\n";}}closedir($handle);
}
?>

<?php
if ($handle = opendir('test')) {while (false !== ($file = readdir($handle))) {if ($file != "." && $file != "..") {$file = "test/".$file;if(is_dir($file)){echo "目录：".$file."<br>";}else{echo "文件：".$file."<br>";}}}closedir($handle);
}
/*
文件：test/a.txt
文件：test/b.txt
目录：test/in*/
?>    

void rewinddir ( resource $dir_handle )

<?php
if ($handle = opendir('test')) {while (false !== ($file = readdir($handle))) {if ($file != "." && $file != "..") {$file = "test/".$file;if(is_dir($file)){echo "目录：".$file."<br>";}else{echo "文件：".$file."<br>";}}}while (false !== ($file = readdir($handle))) {if ($file != "." && $file != "..") {$file = "test/".$file;if(is_dir($file)){echo "目录：".$file."<br>";}else{echo "文件：".$file."<br>";}}}closedir($handle);
}/*
文件：test/a.txt
文件：test/b.txt
目录：test/in*/
?>

<?php
if ($handle = opendir('test')) {while (false !== ($file = readdir($handle))) {if ($file != "." && $file != "..") {$file = "test/".$file;if(is_dir($file)){echo "目录：".$file."<br>";}else{echo "文件：".$file."<br>";}}}rewinddir($handle);while (false !== ($file = readdir($handle))) {if ($file != "." && $file != "..") {$file = "test/".$file;if(is_dir($file)){echo "目录：".$file."<br>";}else{echo "文件：".$file."<br>";}}}closedir($handle);
}/*
文件：test/a.txt
文件：test/b.txt
目录：test/in
文件：test/a.txt
文件：test/b.txt
目录：test/in*/
?>

float disk_total_space ( string $directory )

<?php
$ds = disk_total_space("C:");
echo $ds."<br>";//126652637184
$ds = disk_total_space("D:");
echo $ds;//1000202240000
?>

float disk_free_space ( string $directory )

<?php
$ds = disk_free_space("C:");
echo $ds."<br>";//86087041024
$ds = disk_free_space("D:");
echo $ds;//481647472640
?>

<?php$dirn = 0; //目录数$filen = 0; //文件数//统计一个目录下的文件和目录的个数function getdirnum($file) {global $dirn;global $filen;    $dir = opendir($file);while (false !== ($filename = readdir($dir))) {if($filename!="." && $filename !="..") {$filename = $file."/".$filename; //更新路径if(is_dir($filename)) {$dirn++;getdirnum($filename);  //递归，就可以查看所有子目录} else {$filen++; }}}closedir($dir);}getdirnum("test");echo "目录数为:{$dirn}<br>";//目录数为:1echo "文件数为:{$filen}<br>";//文件数为:3
?>

<?php//统计目录大小function dirsize($file) {$size = 0;$dir = opendir($file);while(false !== ($filename = readdir($dir))) {if($filename!="." && $filename !="..") {$filename = $file."/".$filename;if(is_dir($filename)) {$size += dirsize($filename);//使用递归} else {$size += filesize($filename);}}}closedir($dir);return $size;}
echo "test目录大小为：".dirsize("test")."<br>";//test目录大小为：302
?>

bool mkdir ( string $pathname [, int $mode = 0777 [, bool $recursive = false [, resource $context ]]] )

bool rmdir ( string $dirname [, resource $context ] )

bool unlink ( string $filename [, resource $context ] )

<?phpfunction deldir($dirname) {//如果是文件，直接删除即可if(is_file($dirname)) {unlink($dirname);}$dir = opendir($dirname);while(FALSE !== ($filename = readdir($dir))) {if($filename !="." && $filename!="..") {$filename = $dirname."/".$filename;if(is_dir($filename)) {deldir($filename);//递归}else {unlink($filename);//删除文件
                }}}closedir($dir);if($dirname != 'test'){rmdir($dirname);//删除目录
        }}deldir("test");
?>

bool copy ( string $source , string $dest [, resource $context ] )

<?php
$file = 'a.txt';
$newfile = 'a.bak';
copy($file, $newfile);
?>

bool rename ( string $oldname , string $newname [, resource $context ] )

<?php
rename("test", "d:/t");
?>

<?php/*** $dirsrc  原目录* $dirto  目标目录*/function copydir($dirsrc, $dirto) {//如果目录不存在，则新建一个目录if(!file_exists($dirto)) {mkdir($dirto);}$dir = opendir($dirsrc);while(FALSE !== ($filename = readdir($dir))) {if($filename != "." && $filename !="..") {$srcfile = $dirsrc."/".$filename;  //原文件$tofile = $dirto."/".$filename;    //目标文件if(is_dir($srcfile)) {copydir($srcfile, $tofile);  //递归处理所有子目录}else{copy($srcfile, $tofile);//复制文件
                }}}}copydir("test", "d:/t");
?>

bool touch ( string $filename [, int $time = time() [, int $atime ]] )

<?phptouch('abc.txt')
?>

bool copy ( string $source , string $dest [, resource $context ] )

<?php
$file = 'a.txt';
$newfile = 'a.bak';
copy($file, $newfile);
?>

bool rename ( string $oldname , string $newname [, resource $context ] )

<?php
rename("abc.txt", "d:/cba.txt");
?>

bool unlink ( string $filename [, resource $context ] )

<?php
unlink("d:/cba.txt");
?>

fopen('test.png',w);

mode      说明
'r'       只读方式打开，将文件指针指向文件头。
'r+'      读写方式打开，将文件指针指向文件头。
'w'       写入方式打开，将文件指针指向文件头并将文件大小截为零。如果文件不存在则尝试创建之。
'w+'      读写方式打开，将文件指针指向文件头并将文件大小截为零。如果文件不存在则尝试创建之。
'a'       写入方式打开，将文件指针指向文件末尾。如果文件不存在则尝试创建之。
'a+'      读写方式打开，将文件指针指向文件末尾。如果文件不存在则尝试创建之。

<?php//使用绝对路径打开file.txt文件，选择只读模式，并返回资源$handle$handle = fopen("/home/rasmus/file.txt", "r");//访问文档根目录下的文件，也以只读模式打开$handle = fopen(“{$_SERVER['DOCUMENT_ROOT']}/data/info.txt", "r");//在 Windows 平台上，转义文件路径中的每个反斜线，或者用斜线，以二进制和只写模式组合$handle = fopen("c:\\data\\file.gif", "wb");//使用相对路径打开file.txt文件，选择只读模式，并返回资源$handle$handle = fopen("../data/info.txt", "r");//打开远程文件， 使用HTTP协议只能以只读的模式打开$handle = fopen("http://www.example.com/", "r");//使用FTP协议打开远程文件，如果FTP服务器可写，则可以以写的模式打开$handle = fopen("ftp://user:password@example.com/somefile.txt", "w");
?>

bool fclose ( resource $handle )

<?php
$handle = fopen('test/a.txt', 'r');
fclose($handle);
?>

int fwrite ( resource $handle , string $string [, int $length ] )

<?php
$fp = fopen('test/a.txt', 'r');
echo fwrite($fp, '1');//0
echo "<br>";
echo fwrite($fp, '23');//0
echo "<br>";
fclose($fp);
?>

<?php
$fp = fopen('test/a.txt', 'w');
echo fwrite($fp, '1');//1
echo "<br>";
echo fwrite($fp, '23');//2
echo "<br>";
fclose($fp);
/*
文件内容为123*/
?>

<?php
$fp = fopen('test/a.txt', 'a');
echo fwrite($fp, '1');//1
echo "<br>";
echo fwrite($fp, '23');//2
echo "<br>";
fclose($fp);
/*
刷新两次时，文件内容为123123*/
?>

string fgetc ( resource $handle )

<?php
$fp = fopen('test/a.txt', 'r');
echo fgetc($fp);//1
echo fgetc($fp);//2
echo fgetc($fp);//3
fclose($fp);
?>

bool feof ( resource $handle )

<?php
$fp = fopen('test/a.txt', 'r');
while(!feof($fp)){echo fgetc($fp);//123123
}
fclose($fp);
?>

string fgets ( resource $handle [, int $length ] )

aa
bbb

<?php
$fp = fopen('test/a.txt', 'r');
echo fgets($fp);//'aa'
echo fgets($fp);//'bbb'
echo fgets($fp);//''
fclose($fp);
?>

string fread ( resource $handle , int $length )

<?php
$fp = fopen('test/a.txt', 'r');
echo fread($fp,3);//'aa '
fclose($fp);$fp = fopen('test/a.txt', 'r');
echo fread($fp,filesize('test/a.txt'));//'aa bbb'
fclose($fp);
?>

int fseek ( resource $handle , int $offset [, int $whence = SEEK_SET ] )    

<?php
$fp = fopen('test/a.txt', 'r');
echo fgetc($fp);//'1'
fseek($fp,4);
echo fgetc($fp);//'5'
fclose($fp);
?>

<?php
$fp = fopen('test/a.txt', 'r');
echo fread($fp,2)."<br>";//12
fseek($fp,4);
echo fread($fp,2)."<br>";//5
fseek($fp,-3,SEEK_END);
echo fread($fp,2)."<br>";//34
fclose($fp);
?>

int ftell ( resource $handle )

<?php
$fp = fopen('test/a.txt', 'r');
echo ftell($fp);//0
fgetc($fp);
echo ftell($fp);//1
fseek($fp,4);
echo ftell($fp);//4
fclose($fp);
?>

bool rewind ( resource $handle )

<?php
$fp = fopen('test/a.txt', 'r');
fseek($fp,2);
echo ftell($fp);//2
rewind($fp);
echo ftell($fp);//0
?>

string file_get_contents ( string $filename [, bool $use_include_path = false [, resource $context [, int $offset = -1 [, int $maxlen ]]]] )

<?php
$homepage = file_get_contents('test/a.txt');
echo $homepage;//'12345'
?>

<?php
$homepage = file_get_contents('http://www.baidu.com/');
echo $homepage;
?>

int file_put_contents ( string $filename , mixed $data [, int $flags = 0 [, resource $context ]] )

<?php
file_put_contents('test/a.txt','abc');
?>

int readfile ( string $filename [, bool $use_include_path = false [, resource $context ]] )

<?php
readfile('http://www.baidu.com/');//页面中显示百度首页
?>
<?php
readfile('test/a.txt');//页面中显示abc
?>

array file ( string $filename [, int $flags = 0 [, resource $context ]] )

<?php
$arr = file('test/a.txt',0);
echo $arr[0]."<br>";//1
echo count($arr);//9
?>

bool ftruncate ( resource $handle , int $size )

<?php
$fp = fopen("test/a.txt","a");
ftruncate($fp,100);
?>

$file = fopen('a.png',w);
fclose($file);

touchu('a.png');

语法： bool flock ( int handle, int operation [, int &wouldblock] )

<?phpheader("Content-Type:text/html;charset=utf8");//功能类似于数据库的文件$filename = "message.txt";//检查函数function test_input($data) {$data = trim($data);$data = stripslashes($data);$data = htmlspecialchars($data);return $data;}//如果用户提交了，就按一定格式写入文件if(isset($_POST['dosubmit'])) {$name = test_input($_POST['username']);$content = test_input($_POST['content']);//字段的分隔使用||，行的分隔使用[n]$mess = "$name||$content||".time()."[n]";//调用写信息函数writemessage($filename, $mess);}//如果文件存在，则读文件内容if(file_exists($filename)) {readmessage($filename);}//写函数function writemessage($filename, $mess) {global $name,$content;//以追加模式打开文件$fp = fopen($filename, "a");//如果锁定成功if(flock($fp, LOCK_EX+LOCK_NB)) {//将数据写入文件if($name && $content){fwrite($fp, $mess);}//释放锁定flock($fp, LOCK_UN+LOCK_NB);}else{echo "写入锁定失败!";}//关闭文件fclose($fp);}//读函数function readmessage($filename) {//以只读模式打开文件$fp = fopen($filename, "r");//读锁定flock($fp, LOCK_SH+LOCK_NB); $mess = "";//将数据遍历到$mess中while(!feof($fp)) {$mess.=fread($fp, 1024);}//释放锁定flock($fp, LOCK_UN+LOCK_NB);if(!empty($mess)){$mess = rtrim($mess, "[n]");//通过[n]将每行留言分割并存入数组中$arrmess = explode("[n]", $mess);foreach($arrmess as $m) {//将每行数据使用'||'分割list($username,$content,$t) = explode("||", $m);date_default_timezone_set('PRC');echo "<b>{$username}</b>说：<u>{$content}</u>(".date('Y-m-d H:i:s',$t).")<hr><br>";}            }//关闭文件fclose($fp);}
?>
<form action="message.php" method="post">用户：<input type="text" name="username" value="" /><br>内容：<textarea  name="content" cols="22" rows="3"></textarea><br><input type="submit" name="dosubmit" value="留言" /><br>
</form>

bool is_uploaded_file ( string $filename )

bool move_uploaded_file ( string $filename , string $destination )

<?php
header("Content-Type:text/plain;charset=utf-8");
//判断错误
if($_FILES['file1']['error'] > 0) {switch($_FILES['file1']['error']) {case 1:case 2:echo "上传文件太大";break;case 3:echo "文件只被部分上传";break;case 4:echo "没有上传任何文件";break;default:echo "末知错误";}exit;
}//判断类型$arr = explode(".", basename($_FILES['file1']['name']));$hz = array_pop($arr);$allowtype =array("gif", "png", "jpg", "jpeg");if(!in_array($hz, $allowtype)) {echo "上传的类型不合法";exit;} //判断大小$maxsize= 1000000;if($_FILES['file1']['size'] > $maxsize) {echo "上传的文件超过了{$maxsize}字节!";exit;}//随机文件名$tmp_name = $_FILES['file1']['tmp_name'];$src_name = "./uploads/".date("YmdHis").rand(100, 999).".".$hz;if(move_uploaded_file($tmp_name, "$src_name")){echo '上传成功';}else{echo '上传失败';}
?>

<a href="http://baidu.com/test/book.rar">下载</a>

void header ( string $string [, bool $replace = true [, int $http_response_code ]] )

<?php//该行不是必须的header('Content-type: image/png');//将文件设置为附件格式(浏览器只会下载而不会打开附件格式)，设置下载时显示的文件名header('Content-Disposition: attachment; filename="downloaded.png"');//读取文件并写入到输出缓冲readfile('./uploads/20170315085246943.png');
?>