I won't pretend that I know what I'm doing with regular expressions.  I
have a string that I want to take a chunk out and replace it with a
system property.  So I might have app.home as a System property with
the value "/opt/application/" and I want to have a method that takes:

"$app.home/config/" and turns it into "/opt/application/config/"

I am not necessarily committed to using a $ like a scripted variable --
I have tried some other things, like @app.home@/config/ and
${app.home}/config/  -- but my regex is never correct.  Here is the
test code I was using for the $app.home I was trying.

I hope someone can see something I'm missing.

Cheers,
Robin

public class EnvRE {

    String s1 = "this/has/$variables.inside/of/it";
    static final String RE = "^(?:.*?)(\\$[\\d\\w\\.]+?)(?:.*?)$";

    public EnvRE() {
        Pattern p = Pattern.compile(RE);
        Matcher m = p.matcher(s1);

        System.out.println("ORIGINAL: " + s1);
        if (m.find()) {
            for (int i = 0; i < m.groupCount(); i++) {
                System.out.println("GROUP " + i + ": " + m.group(i));
            }
        }
    }

    public static void main(String[] args) {
        new EnvRE();
    }
}

Here's my output when I run this:

ORIGINAL: this/has/$variables.inside/of/it
GROUP 0: this/has/$variables.inside/of/it