What are some common functions in PHP for file handling and manipulation?

When working with files in PHP, there are several common functions that can be used for handling and manipulating files. Some of these functions include fopen() for opening a file, fwrite() for writing to a file, fclose() for closing a file, file_get_contents() for reading a file into a string, and file_put_contents() for writing a string to a file.

// Example of reading a file using file_get_contents()
$file_contents = file_get_contents('example.txt');
echo $file_contents;