What are the potential pitfalls of using CLI input for file processing in PHP?

Potential pitfalls of using CLI input for file processing in PHP include security vulnerabilities such as command injection attacks and improper handling of user input leading to unexpected behavior or errors. To mitigate these risks, it is important to sanitize and validate user input before using it in file operations.

// Sanitize and validate user input before using it in file operations
$filename = filter_var($argv[1], FILTER_SANITIZE_STRING);

// Check if the file exists before processing it
if (file_exists($filename)) {
    // Proceed with file processing
} else {
    echo "File does not exist.";
}