diff --git a/src/Console/Command/GenerateCommand.php b/src/Console/Command/GenerateCommand.php
index 05c256e..6de81d7 100644
--- a/src/Console/Command/GenerateCommand.php
+++ b/src/Console/Command/GenerateCommand.php
@@ -4,8 +4,8 @@ namespace Opdavies\GmailFilterBuilder\Console\Command;
 
 use Opdavies\GmailFilterBuilder\Builder;
 use Symfony\Component\Console\Command\Command;
-use Symfony\Component\Console\Input\InputArgument;
 use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Input\InputOption;
 use Symfony\Component\Console\Output\OutputInterface;
 use Symfony\Component\Console\Style\SymfonyStyle;
 
@@ -21,8 +21,8 @@ class GenerateCommand extends Command
         $this
             ->setName(self::NAME)
             ->setDefinition([
-                new InputArgument('input-file', InputArgument::OPTIONAL, 'The name of the PHP file containing your filters.', 'filters.php'),
-                new InputArgument('output-file', InputArgument::OPTIONAL, 'The name of the XML file to generate.', 'filters.xml')
+                new InputOption('input-file', null, InputOption::VALUE_OPTIONAL, 'The name of the PHP file containing your filters.', 'filters.php'),
+                new InputOption('output-file', null, InputOption::VALUE_OPTIONAL, 'The name of the XML file to generate.', 'filters.xml')
             ])
             ->setDescription('Generates XML for Gmail filters.')
         ;
@@ -33,8 +33,8 @@ class GenerateCommand extends Command
      */
     protected function execute(InputInterface $input, OutputInterface $output)
     {
-        $inputFile = $input->getArgument('input-file');
-        $outputFile = $input->getArgument('output-file');
+        $inputFile = $input->getOption('input-file');
+        $outputFile = $input->getOption('output-file');
 
         if (file_exists(__DIR__.'/../../../../'.$inputFile)) {
             $filters = require(__DIR__.'/../../../../'.$inputFile);