File Handling in PHP

There are many built-in functions in PHP to handle files and directories. Using these functions we can read, write, delete, and get lots of information of the files. To perform any funtion on a file we should have the right permission which will allow us to manupulate that file.

Creating and Deleting a File

We can create a file using the funtion "touch()". The touch() funtion when called first searches whether the specified file exists or not if the file doesnot exists it creates one with the specfied file name. To delete a file we use the function called "unlink()". This funtion removes the file that has been sent as an argument.

touch(�newinfo.txt�); //create a new file, if it doesn�t already exist

unlink(�oldinfo.txt�); //delete a file

Open Existing File

When a file got created, How to access it?
We can access an existing file using the funtion called "fopen()". This funtion takes two arguments, The first argument specifies the name of the file that has to be opened, and the second argument specifies in which mode the file has to be opened.i'e in "read-r", "write-w" or both "read-write" mode.

If the function fopen() executes successfully then it returns an integer value known as a file pointer. This value should be stored in a variable. This variable is used to work on with the opened file. If the funtion fopen() fails executing for any reason, It just returns FALSE. Once the file is used we should close it using the "fclose()" function. This function takes only the file name as the argument.

$oldfp = fopen(�oldinfo.txt�, �r�); //opens a file for reading

if(!$fp = fopen(�newinfo.txt�, �w�)) //tries to open a file for writing

die(�Error on opening file!�); //terminates the execution of the script if it cannot open the file

fclose($oldfp);

Reading from Files

To read from the file we use the funtion called "fgets()". When this funtion is called, it reads out all the characters until a newline(\n), or End Of File(EOF), or till a specified length is reached.

The function "fgets()" is similar to "fgets()", Unlike fgets() it returns a single character from a file. there is no need to specify any length as a argument, since a character is always 1 byte.

$text = fgets($fp, 2000); //reads 2000 bytes at most

$chr = fgetc($fp); //reads 1 byte only

More File Handling Functions

There are a lot of other functions that you can use with files like: testing functions � �file_exists()�, �is_file()�, �is_dir()�, �is_readable()�, �is_writeable()�, �is_executable()�; functions that return information on files: �filesize()�, �fileatime()�, �filemtime()�, �filectime()�. You can figure out what the function does by just reading its name.

Following table contains few File Handling functions and their description

Example	Description Preview
chdir	Changes PHP's current directory to specified directory. Returns TRUE on success or FALSE on failure.
chroot	Change the root directory
closedir	Closes a directory handle previously opened with opendir().
copy	Makes a copy of a file. Returns TRUE if the copy succeeded, FALSE otherwise.
dir	dir -- directory class class dir { dir(string directory); string path; resource handl...
file	Returns the contents of a file in an array.
filesize	Gets file size
fopen	Opens a file handle to be used .
fread	Reads the contents of a file descriptor assigned with fopen().
fwrite	Writes to a file descriptor opened with fopen().
getcwd	gets the current working directory string. getcwd (void) Returns the current working directory.
opendir	Returns a directory handle that can be used with readdir(), closedir() and rewinddir().
readdir	Reads the next file from a directory handle opened with opendir().
rename	Renames a file from the old file name to the new file name.
rewinddir	rewind directory handle, void rewinddir ( resource dir_handle) Resets the directory stream indicated by dir_handle to the beginning of the directory.
scandir	List files and directories inside the specified path
Unlink	Deletes a file.