PHP Learning Basics-File System (i) file processing, file permissions

First, the PHP system file processing

/* PHP File System processing * All file processing is done using system functions. * is based on LINUX/UNIX system for Model * * File system processing function: * 1. All projects are inseparable from file processing * 2. You can save data for long periods of time with a file * 3. Establish the cache, the server file operation * * File processing * * *. File type * Linux-model, in Windows can only get file, dir or unknow three types * under Linux/unix, block, Char, dir, FIFO, file, link, unknown and type *block: Block settings files, disk partitions, floppy drives, CD-ROM, etc. *char: Character devices, I/O in characters, keyboards, printers, etc. *dir: Directories are also a *fifo of files: *file: *link: *unknown * * filetype ("directory or file Name ") * * Is_array (); * Is_int (); * Is_string (); * IS_NULL; * Is_bool (); * Is_dir--to determine whether a given file name is a directory is_executable--to determine whether a given file name can be executed Is_file--to determine whether a given file name is a normal file Is_link--to determine whether the given file name is a symbolic connection is_ Readable--to determine whether a given file name is readable Is_uploaded_file--to determine if a file is uploaded via HTTP POST is_writable--to determine if a given file name can be written is_writeable--is_writable ( ) is an alias * * * *. The properties of the file *file_exists (); *filesize (); *is_readable (); *is_writeable (); *filectime (); *filemtime (); *fileactime (); *stat (); * * *.  Functions related to file path * * Relative path: In relation to the ancestor and subordinate directories of the current directory *. Current directory *.. Previous level directory * *./php/apache/index.php *php/apahce/index.php *login.php *./login.php *. /images/tpl/logo.gif * * * path delimited symbol *linux/unix "/" *windows "\" * *directory_separator for different platforms in Windows \ Linux/* * No matter what operating system PHP directory split symbols are supported/(Linux) * in P                              In HP and Apache configuration files if you need to specify directories, also use/as directory symbols * * Absolute path: */root Path * */images/index.php * * refers to the root of the operating system * refers to the document root directory of the site * * Sub-condition * * If the path is executed in the server (via PHP file handler) the "root" refers to the root of the operating system * If the program is a downloaded client and then accesses the file on the server, only the APA Che access, "root" also refers to the document root directory * *http://www.xsphp.com/logo.gif * * *basename (URL) *dirname (URL) *pathinfo (URL) * * * * * *. File operations (create files, delete files, move files). Open and close the file (read the contents of the file, write to the file) *6. Move the pointer *7 inside the file. File locking some mechanisms for processing * * * Directory processing * 1. The traversal of the directory * 2. Creation of the directory * 3. Deletion of the directory * 4. The replication of the directory. Statistics Directory Size * * * File upload and download * 1. Upload * 2. Download * * * *

Second, PHP file attribute function instance

Date_default_timezone_set ("PRC"); function Getfilepro ($fileName) {if (!file_exists ($fileName)) {echo "file or directory {$ FileName} does not exist
"; return;} Else{echo "type of File". FileType ($fileName). "
";} if (Is_file ($fileName)) {echo "This is a file
The size of the "; echo" file is ". GetFileSize (FileSize ($fileName))."
";} if (Is_dir ($fileName)) {echo "This is a directory
";} if (is_readable ($fileName)) {echo "This file can be read
";} if (is_writable ($fileName)) {echo "This file can be written
";} if (is_executable ($fileName)) {echo "This file can be executed
";} echo "File creation time:". Date ("Y-m-d h:i:s", Filectime ($fileName)). "
Modified time for "; echo" File: ". Date (" Y-m-d h:i:s ", Filemtime ($fileName))."
Last access time for "; echo" File: ". Date (" Y-m-d h:i:s ", Fileatime ($fileName))."
";} function GetFileSize ($size) {$DW = "Byte", if ($size >= pow (2)) {$size =round ($size/pow (2, 2); $DW = "TB";} else if ($size >= pow (2)) {$size =round ($size/pow (2), 2); $DW = "GB";} else if ($size >= pow (2)) {$size =round ($size/pow (2), 2); $DW = "MB";} else if ($size >= pow (2)) {$size =round ($size/pow (2, Ten), 2); $DW = "KB";} else {$DW = "Bytes";} return $size. $dw;} Getfilepro ("Demo.txt"); Getfilepro ("Hello");

Third, PHP gets the file status function

Date_default_timezone_set ("PRC"); Echo '
';p Rint_r (stat ("Demo.txt")); Echo '
';

Iv. using File system cache data scheme

$cache =5;                   Cache time $cachefile= "Cache.txt";      Cached Files if (file_exists ($cachefile) && (Time ()-$cache) < Filemtime ($cachefile)) {   echo file_get_ Contents ($cachefile); If within 10 seconds of the cache, the data}else{file_put_contents ($cachefile, Date ("Y-m-d h:i:s", Time ()) is obtained from the cache file;}

Five, file path correlation function instance

$url 1= "./aaa/bbb/index.php"; Echo basename ($url 1). "
";  File name Echo dirname (dirname ($url 1)). "
"; Parent directory Echo dirname ($url 1). "
"; File directory echo '
';       File path information  print_r ($path =pathinfo ($url 3));  Echo '
';    echo $path ["extension"];

Vi. file system permissions-related function instances

  Create a file Touch ("filename") to  delete the file unlink ("File path");  Move the file to rename the file rename ("Current file path", "Directory for File Path") to  Copy the file ("current", "target");   Be sure to have PHP execute this file permission, Apache, a user    and permission design related function    ls-l  or ll  _rwxrwxrwx   777  _ type _ file  D means directory  l  B     rwx table The owner of this file  R Read W write x execute      rwx table The owner of this file the group  R Read W write x perform  rwx other users to this permission for the file  R read W write X perform r 4w 2x 1 7 7 7  4+2+1  4+2+1 4+2+1rwx   rwx  rwx6444+2   4   4rw_  r__ r__754  chmod u=rwx,g=rw,o=x  chmod 777  demo.php  chmod 644  demo.html  chown  MySQL demo.php  chgrp  Apache demo.php  chgrp--Change the group chmod the file belongs to--  change  The file mode chown--Change the file owner  filegroup-- Get the file group  Fileowner--Get the owner of the file

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