function randchar() 
{
	chars = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";
	c = rand() * length(chars);
	return substr(chars, c, 1);
}

/\$\$/ {
	for ( i = 1 ; i <= NF ; i++ )
	{
		
		if ($i == "$$") {
			printf("%c%c ", randchar(), randchar());
		}
		else
			printf("%s ", $i);
	}
	printf("\n");
	next;
}
/.*/ { print }