use Mojolicious::Lite;
    use Mojo::IOLoop::Subprocess;
...
post '/' => sub {
...
    my $message = 'INFO: Something useful';
    my $cmd = 'cd /home/foo/bar && ./some-script.pl >some.out 2>some.err';

    my $subprocess = Mojo::IOLoop::Subprocess->new;
    $subprocess->run(

      sub {

        my $subprocess = shift;
        my $result = qx/$cmd/;

        return $result;
      },  
      sub {

        my ($subprocess, $err, @results) = @_; 
        if ( $err ) { $message .= "ERROR: $err"; }
        else { $message = $results[0]; }
      }   
    );  

    $subprocess->ioloop->start unless $subprocess->ioloop->is_running;
...
    $c->render(template => 'index');
};