FileSystem Function in PHP: PART 11

Introduction

In this article I describe the PHP FileSystem functions ftell, ftruncate, fwrite and glob. To learn some other FileSystem functions, go to:

1. FileSystem Function in PHP: PART 1
2. FileSystem Function in PHP: PART 2
3. FileSystem Function in PHP: PART 3
4. FileSystem Function in PHP: PART 4
5. FileSystem Function in PHP: PART 5
6. FileSystem Function in PHP: PART 6
7. FileSystem Function in PHP: PART 7
8. FileSystem Function in PHP: PART 8
9. FileSystem Function in PHP: PART 9
10. FileSystem Function in PHP: PART 10

PHP ftell() Function

The PHP FileSystem ftell function is used to fetch the current position of the file pointer of an open file and it returns the current position in an open file.

Syntax

fread(file)

Parameters in ftell function

The parameter of the function is:

Parameter	Description
file	It specifies the open file to check.

Example of ftell function

An example of the function is:

<?php
$file = fopen("test.txt","r");
echo ftell($file);
fseek($file,"15");
// print current position again
echo "<br />" . ftell($file);
fclose($file);
?>

Output



PHP ftruncate() Function

The PHP FileSystem ftruncate function is used to truncates a file to a specified length and it returns true on success or false on failure.

Syntax

fread(file,size)

Parameters in ftruncate function

The parameter of the function are:

Parameter	Description
file	It specifies the open file to truncate.
size	It specifies the new file size.

Example of ftruncate function

An example of the function is:

<?php
echo filesize("test.txt")."</br>";
$file = fopen("test.txt", "a+");
ftruncate($file,50);
fclose($file);
//Clear cache and check filesize again
clearstatcache();
echo filesize("test.txt");
?>
 
Output



PHP fwrite() Function

The PHP FileSystem fwrite is used to write to an open file and it returns number of bytes on success or false on failure.

Syntax

fread(file,string, length)

Parameters in fwrite function

The parameters of the function are:

Parameter	Description
file	It specifies the open file to truncate.
string	It specifies the string to the open file.
length	It specifies the maximum number of bytes to write.

Example of fwrite function

An example of the function is:

<?php
$fileHandler = fopen("test.txt", "w");
// Write to the file
fwrite($fileHandler, "Welcome at MCNSolution!");
fclose($fileHandler);
// Access the file data and echo it
$data = file_get_contents("test.txt");
echo $data;
?>
 
Output



PHP glob() Function

The PHP FileSystem glob function returns an array of filenames or directories matching a specified pattern.

Syntax

glob(pattern,flag)

Parameters in fwrite function

The parameters of the function are:

Parameter	Description
pattern	It specifies the pattern to search for.
flag	It specifies special settings and the possible values are: GLOB_MARK - Adds a slash to each item returned. GLOB_NOSORT - Return files as they appear in the directory. GLOB_NOCHECK - Returns the search pattern if no match were found. GLOB_NOESCAPE - Backslashes do not quote metacharacters. GLOB_BRACE - Expands {a,b,c} to match "a", "b", or "c". GLOB_ONLYDIR - Return only directories that match the pattern. GLOB_ERR - Stop on errors.

Example of glob function

An example of the function is:

<?php
print_r(glob("*.txt"));
?>
 
Output