Introduction
In this article I describe the PHP FileSystem functions popen, readfile, readlink, realpath and rename. To learn some other FileSystem functions, go to:
- FileSystem Function in PHP: PART 1
- FileSystem Function in PHP: PART 2
- FileSystem Function in PHP: PART 3
- FileSystem Function in PHP: PART 4
- FileSystem Function in PHP: PART 5
- FileSystem Function in PHP: PART 6
- FileSystem Function in PHP: PART 7
- FileSystem Function in PHP: PART 8
- FileSystem Function in PHP: PART 9
- FileSystem Function in PHP: PART 10
- FileSystem Function in PHP: PART 11
- FileSystem Function in PHP: PART 12
- FileSystem Function in PHP: PART 13
- FileSystem Function in PHP: PART 14
- FileSystem Function in PHP: PART 15
PHP popen() Function
The PHP FileSystem popen function opens a process's file pointer; in other words it returns a file pointer, identical to that returned by fopen or returns false if an error occurs.
Syntax
Parameter in popen function
The parameters of the function are:
Parameter |
Description |
command |
It specifies the command to execute. |
mode |
It specifies the connection mode and the possible values are:
- r: read only
- w: write only.
|
Example
An example of the function is:
<?php
$file=popen('/bin/ls','r');
pclose($file);
?>
PHP readfile() Function
The PHP FileSystem readfile function is used to read a file and places the data in a buffer and it returns the number of bytes read from the file or false if an error occurs.
Syntax
readfile(filename,includepath,context) |
Parameter in popen function
The parameters of the function are:
Parameter |
Description |
file |
It specifies the file to read. |
includePath |
It is an optional parameter; it is is set to 1 (one) to search for the file in the include path. |
context |
It specifies the context of the file handle. |
Example
An example of the function is:
<?php
echo readfile("test.txt");
?>
Output
PHP readlink() Function
The PHP FileSystem readfile function returns the target of a symbolic link or say this function returns the target on success or false on failure.
Syntax
Parameter in readlink function
The parameter of the function is:
Parameter |
Description |
linkPath |
It specifies the link path to check. |
Example
An example of the function is:
<?php
echo readlink("/wamp/test");
?>
PHP realpath() Function
The PHP FileSystem realpath function returns the absolute path name, in other words it returns the absolute pathname on success or returns false on failure.
Syntax
Parameter in realpath function
The parameter of the function is:
Parameter |
Description |
path |
It specifies the path to check. |
Example
An example of the function is:
<?php
echo realpath("test.txt");
?>
Output
PHP reaname() Function
The PHP FileSystem rename function renames a file or directory and it returns true on success or false on failure.
Syntax
rename(oldname,newname,context) |
Parameter in rename function
The parameter of the function is:
Parameter |
Description |
oldname |
It specifies the file or directory to be renamed. |
newname |
It specifies the new name of the file or directory . |
context |
It specifies the context of the file handle. |
Example
An example of the function is:
<?php
rename("xyz.jpg","abc.jpg");
if(file_exists("abc.jpg"))
{
echo "File has been renamed";
}
else
{
echo "File has not been renamed";
}
?>
Output