我的书签
添加书签
移除书签Filesystem Functions
Filesystem Functions
basename
Name
basename — return filename component of path
Description
string basename(string path);
chgrp
Given a string containing a path to a file, this function will return the base name of the file.
On Windows, both slash (/) and backslash (\) are used as path separator character. In other environments, it is the forward slash (/).
Example 1. basename example
$path = "/home/httpd/html/index.php3";
$file = basename($path); // $file is set to "index.php3"
See also: dirname
Name
chgrp — change file group
Description
int chgrp(string filename, mixed group);
Attempts to change the group of the file filename to group. Only the superuser may change the group of a file arbitrarily; other users may change the group of a file to any group of which that user is a member.
Returns true on success; otherwise returns false. On Windows, does nothing and returns true.
See also chown and chmod.
chmod
Name
chmod — change file mode
Description
int chmod(string filename, int mode);
Attempts to change the mode of the file specified by filename to that given in mode.
Note that mode is not automatically assumed to be an octal value. To ensure the expected operation, you need to prefix mode with a zero (0):
chmod( "/somedir/somefile", 755 ); // decimal; probably incorrect chmod( "/somedir/somefile", 0755 ); // octal; correct value of mode
Returns true on success and false otherwise. See also chown and chgrp.
chown
Name
chown — change file owner
Description
int chown(string filename, mixed user);
Attempts to change the owner of the file filename to user user. Only the superuser may change the owner of a file.
Returns true on success; otherwise returns false.
On Windows, does nothing and returns true.
See also chown and chmod.
clearstatcache
Name
clearstatcache — clear file stat cache
Description
void clearstatcache(void);
copy
Invoking the stat() or lstat() system call on most systems is quite expensive. Therefore, the result of the last call to any of the status functions (listed below) is stored for use on the next such call using the same filename. If you wish to force a new status check, for instance if the file is being checked many times and may change or disappear, use this function to clear the results of the last call from memory.
Affected functions include stat, lstat, file_exists, is_writeable, is_readable, is_executable, is_file, is_dir, is_link, filectime, fileatime, filemtime, fileinode, filegroup, fileowner, filesize, filetype, and fileperms.
Name
copy — copy file
Description
int copy(string source, string dest);
Makes a copy of a file. Returns true if the copy succeeded, false otherwise.
Example 1. copy example
if (!copy($file, $file.'.bak')) { print("failed to copy $file...<br>\n");
}
See also: rename
dirname
Name
dirname — return directory name component of path
Description
string dirname(string path);
Given a string containing a path to a file, this function will return the name of the directory.
On Windows, both slash (/) and backslash (\) are used as path separator character. In other environments, it is the forward slash (/).
Example 1. dirname example
$path = "/etc/passwd";
$file = dirname($path); // $file is set to "/etc"
See also: basename
fclose
Name
fclose — close an open file pointer
Description
int fclose(int fp);
The file pointed to by fp is closed.
Returns true on success and false on failure.
The file pointer must be valid, and must point to a file successfully opened by fopen or fsockopen.
feof
fgetc
Name
feof — test for end-of-file on a file pointer
Description
int feof(int fp);
Returns true if the file pointer is at EOF or an error occurs; otherwise returns false.
The file pointer must be valid, and must point to a file successfully opened by fopen, popen, or
fsockopen.
Name
fgetc — get character from file pointer
Description
string fgetc(int fp);
Returns a string containing a single character read from the file pointed to by fp. Returns FALSE on EOF (as does feof).
The file pointer must be valid, and must point to a file successfully opened by fopen, popen, or
fsockopen.
See also fopen, popen, fsockopen, and fgets.
fgets
Name
fgets — get line from file pointer
Description
string fgets(int fp, int length);
Returns a string of up to length - 1 bytes read from the file pointed to by fp. Reading ends when length - 1 bytes have been read, on a newline, or on EOF (whichever comes first).
If an error occurs, returns false.
The file pointer must be valid, and must point to a file successfully opened by fopen, popen, or
fsockopen.
See also fopen, popen, fgetc, and fsockopen.
fgetss
Name
fgetss — get line from file pointer and strip HTML tags
Description
file
string fgetss(int fp, int length);
Identical to fgets, except that fgetss attempts to strip any HTML and PHP tags from the text it reads. See also fgets, fopen, fsockopen, and popen.
Name
file — read entire file into an array
Description
array file(string filename);
Identical to readfile, except that file() returns the file in an array. See also readfile, fopen, and popen.
file_exists
Name
file_exists — Check whether a file exists.
Description
int file_exists(string filename);
Returns true if the file specified by filename exists; false otherwise. See also clearstatcache.
fileatime
Name
fileatime — get last access time of file
Description
int fileatime(string filename);
Returns the time the file was last accessed, or false in case of an error.
filectime
Name
filectime — get inode modification time of file
Description
int filectime(string filename);
Returns the time the file was last changed, or false in case of an error.
filegroup
Name
filegroup — get file group
Description
int filegroup(string filename);
Returns the group ID of the owner of the file, or false in case of an error.
fileinode
Name
fileinode — get file inode
Description
int fileinode(string filename);
Returns the inode number of the file, or false in case of an error.
filemtime
Name
filemtime — get file modification time
Description
int filemtime(string filename);
Returns the time the file was last modified, or false in case of an error.
fileowner
Name
fileowner — get file owner
Description
int fileowner(string filename);
Returns the user ID of the owner of the file, or false in case of an error.
fileperms
Name
fileperms — get file permissions
Description
int fileperms(string filename);
Returns the permissions on the file, or false in case of an error.
filesize
Name
filesize — get file size
Description
int filesize(string filename);
Returns the size of the file, or false in case of an error.
filetype
Name
filetype — get file type
Description
string filetype(string filename);
Returns the type of the file. Possible values are fifo, char, dir, block, link, file, and unknown. Returns false if an error occurs.
fopen
Name
fopen — open file or URL
Description
int fopen(string filename, string mode);
If filename begins with "http://" (not case sensitive), an HTTP 1.0 connection is opened to the specified server and a file pointer is returned to the beginning of the text of the response.
Does not handle HTTP redirects, so you must include trailing slashes on directories.
If filename begins with "ftp://" (not case sensitive), an ftp connection to the specified server is opened and a pointer to the requested file is returned. If the server does not support passive mode ftp, this will fail.
If filename begins with anything else, the file will be opened from the filesystem, and a file pointer to the file opened is returned.
If the open fails, the function returns false.
mode may be any of the following:
-
'r' - Open for reading only; place the file pointer at the beginning of the file.
-
'r+' - Open for reading and writing; place the file pointer at the beginning of the file.
-
'w' - Open for writing only; place the file pointer at the beginning of the file and truncate the file to zero length. If the file does not exist, attempt to create it.
-
'w+' - Open for reading and writing; place the file pointer at the beginning of the file and truncate the file to zero length. If the file does not exist, attempt to create it.
-
'a' - Open for writing only; place the file pointer at the end of the file. If the file does not exist, attempt to create it.
-
'a+' - Open for reading and writing; place the file pointer at the end of the file. If the file does not exist, attempt to create it.
As well, mode may contain the letter 'b'. This is useful only on systems which differentiate between binary and text files (i.e., it's useless on Unix). If not needed, this will be ignored.
Example 1. fopen() example
$fp = fopen( "/home/rasmus/file.txt", "r" );
$fp = fopen( "http://www.php.net/", "r" );
If you are experiencing problems with reading and writing to files and you're using the server module version of PHP, remember to make sure that the files and directories you're using are accessible to the server process.
See also fclose, fsockopen, and popen.
fpassthru
Name
fpassthru — output all remaining data on a file pointer
Description
int fpassthru(int fp);
fputs
fread
Reads to EOF on the given file pointer and writes the results to standard output. If an error occurs, fpassthru returns false.
The file pointer must be valid, and must point to a file successfully opened by fopen, popen, or
fsockopen. The file is closed when fpassthru is done reading it (leaving fp useless).
If you just want to dump the contents of a file to stdout you may want to use the readfile, which saves you the fopen call.
See also readfile, fopen, popen, and fsockopen
Name
fputs — write to a file pointer
Description
int fputs(int fp, string str, int [length]);
fputs is an alias to fwrite, and is identical in every way. Note that the length parameter is optional and if not specified the entire string will be written.
Name
fread — Binary-safe file read
Description
string fread(int fp, int length);
fread reads up to length bytes from the file pointer referenced by fp. Reading stops when length
bytes have been read or EOF is reached, whichever comes first.
// get contents of a file into a string
$filename = "/usr/local/something.txt";
$fd = fopen( $filename, "r" );
$contents = fread( $fd, filesize( $filename ) ); fclose( $fd );
fseek
ftell
See also fwrite, fopen, fsockopen, popen, fgets, fgetss, file, and fpassthru.
Name
fseek — seek on a file pointer
Description
int fseek(int fp, int offset);
Sets the file position indicator for the file referenced by fp to offset bytes into the file stream. Equivalent to calling (in C) fseek( fp, offset, SEEK_SET ).
Upon success, returns 0; otherwise, returns -1. Note that seeking past EOF is not considered an error. May not be used on file pointers returned by fopen if they use the "http://" or "ftp://" formats.
See also ftell and rewind.
Name
ftell — tell file pointer read/write position
Description
int ftell(int fp);
Returns the position of the file pointer referenced by fp; i.e., its offset into the file stream. If an error occurs, returns false.
The file pointer must be valid, and must point to a file successfully opened by fopen or popen. See also fopen, popen, fseek and rewind.
fwrite
is_dir
Name
fwrite — Binary-safe file write
Description
int fwrite(int fp, string string, int [length]);
fwrite writes the contents of string to the file stream pointed to by fp. If the length argument is given, writing will stop after length bytes have been written or the end of string is reached, whichever comes first.
Note that if the length argument is given, then the magic_quotes_runtime configuration option will be ignored and no slashes will be stripped from string.
See also fread, fopen, fsockopen, popen, and fputs.
Name
is_dir — tells whether the filename is a directory
Description
bool is_dir(string filename);
Returns true if the filename exists and is a directory. See also is_file and is_link.
is_executable
Name
is_executable — tells whether the filename is executable
Description
bool is_executable(string filename);
Returns true if the filename exists and is executable. See also is_file and is_link.
is_file
Name
is_file — tells whether the filename is a regular file
Description
bool is_file(string filename);
Returns true if the filename exists and is a regular file. See also is_dir and is_link.
is_link
Name
is_link — tells whether the filename is a symbolic link
Description
bool is_link(string filename);
Returns true if the filename exists and is a symbolic link. See also is_dir and is_file.
is_readable
Name
is_readable — tells whether the filename is readable
Description
bool is_readable(string filename);
Returns true if the filename exists and is readable.
Keep in mind that PHP may be accessing the file as the user id that the web server runs as (often 'nobody'). Safe mode limitations are not taken into account.
See also is_writeable.
is_writeable
Name
is_writeable — tells whether the filename is writeable
Description
bool is_readable(string filename);
link
Returns true if the filename exists and is writeable.
Keep in mind that PHP may be accessing the file as the user id that the web server runs as (often 'nobody'). Safe mode limitations are not taken into account.
See also is_readable.
Name
link — Create a hard link
Description
int link(string target, string link);
Link creates a hard link.
See also the symlink to create soft links, and readlink along with linkinfo.
linkinfo
Name
linkinfo — Get information about a link
Description
int linkinfo(string path);
Linkinfo returns the st_dev field of the UNIX C stat structure returned by the lstat system call. This function is used to verify if a link (pointed to by path) really exists (using the same method as the S_ISLNK macro defined in stat.h). Returns 0 or FALSE in case of error.
See also symlink, link, and readlink.
mkdir
Name
mkdir — make directory
Description
int mkdir(string pathname, int mode);
Attempts to create the directory specified by pathname. Returns true on success and false on failure.
See also rmdir.
pclose
Name
pclose — close process file pointer
Description
int pclose(int fp);
Closes a file pointer to a pipe opened by popen.
The file pointer must be valid, and must have been returned by a successful call to popen. Returns the termination status of the process that was run.
See also popen.
popen
Name
popen — open process file pointer
Description
int popen(string command, string mode);
Opens a pipe to a process executed by forking the command given by command.
Returns a file pointer identical to that returned by fopen, except that it is unidirectional (may only be used for reading or writing) and must be closed with pclose. This pointer may be used with fgets, fgetss, and fputs.
If an error occurs, returns false.
$fp = popen( "/bin/ls", "r" );
See also pclose.
readfile
Name
readfile — output a file
Description
int readfile(string filename);
Reads a file and writes it to standard output.
Returns the number of bytes read from the file. If an error occurs, false is returned and unless the function was called as @readfile, an error message is printed.
If filename begins with "http://" (not case sensitive), an HTTP 1.0 connection is opened to the specified server and the text of the response is written to standard output.
Does not handle HTTP redirects, so you must include trailing slashes on directories.
If filename begins with "ftp://" (not case sensitive), an ftp connection to the specified server is opened and the requested file is written to standard output. If the server does not support passive mode ftp, this will fail.
If filename begins with neither of these strings, the file will be opened from the filesystem and its contents written to standard output.
See also fpassthru, file, and fopen.
readlink
Name
readlink — Return the target of a symbolic link
Description
string readlink(string path);
Readlink does the same as the readlink C function and returns the contents of the symbolic link path or 0 in case of error.
See also symlink, readlink and linkinfo.
rename
Name
rename — rename a file
Description
int rename(string oldname, string newname);
Attempts to rename oldname to newname. Returns true on success and false on failure.
rewind
Name
rewind — rewind the position of a file pointer
Description
int rewind(int fp);
Sets the file position indicator for fp to the beginning of the file stream. If an error occurs, returns 0.
The file pointer must be valid, and must point to a file successfully opened by fopen. See also fseek and ftell.
rmdir
stat
Name
rmdir — remove directory
Description
int rmdir(string dirname);
Attempts to remove the directory named by pathname. The directory must be empty, and the relevant permissions must permit this.
If an error occurs, returns 0. See also mkdir.
Name
stat — give information about a file
Description
array stat(string filename);
Gathers the statistics of the file named by filename.
Returns an array with the statistics of the file with the following elements:
-
device
-
inode
-
number of links
-
user id of owner
-
group id owner
-
device type if inode device *
-
size in bytes
-
time of last access
-
time of last modification
-
time of last change
-
blocksize for filesystem I/O *
-
number of blocks allocated
- - only valid on systems supporting the st_blksize type--other systems (i.e. Windows) return -1
lstat
Name
lstat — give information about a file or symbolic link
Description
array lstat(string filename);
Gathers the statistics of the file or symbolic link named by filename. This function is identical to the stat function except that if the filename parameter is a symbolic link, the status of the symbolic link is returned, not the status of the file pointed to by the symbolic link.
Returns an array with the statistics of the file with the following elements:
-
device
-
inode
-
number of links
-
user id of owner
-
group id owner
-
device type if inode device *
-
size in bytes
-
time of last access
-
time of last modification
-
time of last change
-
blocksize for filesystem I/O *
-
number of blocks allocated
* - only valid on systems supporting the st_blksize type--other systems (i.e. Windows) return -1
symlink
Name
symlink — Create a symbolic link
Description
int symlink(string target, string link); Symlink creates a symbolic link.
See also link to create hard links, and readlink along with linkinfo.
tempnam
Name
tempnam — create unique file name
Description
string tempnam(string dir, string prefix);
Creates a unique temporary filename.
Returns the new temporary filename, or the null string on failure.
touch
Example 1. tempnam() example
$tmpfname = tempnam( "/tmp", "FOO" );
Name
touch — set modification time of file
Description
int touch(string filename, int time);
Attempts to set the modification time of the file named by filename to the value given by time. If the option time is not given, uses the present time.
If the file does not exist, it is created. Returns true on success and false otherwise.
umask
Name
umask — changes the current umask
Description
int umask(int mask);
Umask sets PHP's umask to mask & 0777 and returns the old umask. When PHP is being used as a server module, the umask is restored when each request is finished.
Umask without arguments simply returns the current umask.
unlink
Name
unlink — Delete a file
Description
int unlink(string filename);
Deletes filename. Similar to the Unix C unlink() function. Returns 0 or FALSE on an error.
See also rmdir for removing directories.
