PHP FILES

Using the PHP file system function fopen(), we can create a new file. Let's look at this function more closely.
fopen ($filename, $mode);
The function fopen() takes in two arguments, the filename and the mode to either open or create a file.
• $filename - the name of the file. This may also include the absolute path where you want to create the file. Example, "/www/myapp/myfile.txt".
• $mode - mode is used to specify how you want to create the file. For example, you can set the mode to create for read only, or create a file for read and write. Below is the list of possible modes you can use.
PHP file fopen create modes
'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, it 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.
For the list of all modes, please see php site.
Create file
Now let see some examples for creating a new files with fopen for reading and writing.
Example 1 - create new file for writing

The code above creates a new file myfile for writing only in the current directory.
The mode "w" creates a new file for writing, places the pointer in the beginning of the file. If the file already existed, it deletes everything in the file.
What happens when fopen fails?
When you create a file, the function fopen returns a file pointer. If the attempt to create a file fails for any reason, the function returns false.
Example 2 - create file for reading and writing

The code above creates a new file as does in example one but it creates the file for both reading and writing in the current directory.
The mode "w+" creates a new file for reading and writing, places the pointer in the beginning of the file. If the file already existed, it deletes everything from the file.
Similarly, you can use mode 'a' and 'a+' for creating new files. However with these modes, if the file already exists, it will not truncate the file (i.e. it will not delete any content in the file) and places the pointer at the end of the file for writing.
So, in the tutorial we learned how to create a new file using the php fopen function, next we will learn how to open existing files for reading and writing using the fopen function.