# PHP File Handling

File handling is an important part of any web application. You often need to open and process a file for different tasks.

---

## 1. Opening and Closing Files
The `fopen()` function is used to open files. It requires two arguments: the file name and the mode.

**Modes:**
*   `r`: Open for reading only.
*   `w`: Open for writing only. Clears file content or creates a new file.
*   `a`: Open for writing only. Appends to end of file or creates a new file.

The `fclose()` function is used to close an open file.

```php
$myfile = fopen("webdictionary.txt", "r") or die("Unable to open file!");
// ... code to read file ...
fclose($myfile);
```

## 2. Reading Files
*   `readfile()`: Reads a file and writes it to the output buffer.
*   `fread()`: Reads from an open file.
*   `fgets()`: Reads a single line from a file.

```php
$myfile = fopen("webdictionary.txt", "r");
echo fread($myfile, filesize("webdictionary.txt"));
fclose($myfile);
```

## 3. Writing to Files
The `fwrite()` function is used to write to a file.

```php
$myfile = fopen("newfile.txt", "w");
$txt = "John Doe\n";
fwrite($myfile, $txt);
fclose($myfile);
```

## 4. Checking if File Exists
Use `file_exists()` to check if a file or directory exists before trying to access it.

```php
if (file_exists("test.txt")) {
    echo "File found.";
} else {
    echo "File not found.";
}
```

[[programming/php/php]]