import java.util.regex.*;
 
class Ideone {
	public static void main (String[] args) {
		String[] names = { "dave", "richard", "danny" };
		System.out.println(parse("hello $2", names));
	}
 
	public static String parse(String command, String[] args) {
    	StringBuffer sb = new StringBuffer();
    	Matcher m = Pattern.compile("\\$(\\d+)").matcher(command);
    	while (m.find()) {
    		int num = Integer.parseInt(m.group(1));
    		m.appendReplacement(sb, args[num - 1]);
    	}
    	m.appendTail(sb);
    	return sb.toString();
	}
}

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