string matches method in java when wanting to compare two dollar signs (not escaping)

Question

I have the simplest of code thats supposed to compare two string inputs as follows:

public class Validate {
    public static void main(String[] args) {
        String re = args[0];

        String input = args[1];

        System.out.println(input.matches(re));
    }
}

It works as expected except if your two inputs are $and$, it just prints out false. I did hear about how you have to escape any special regex characters, including dollar sign.

But what if you want to compare two dollar signs and print out true

`String.matches` uses regex and the `$` is important for regex. You should use `String.equals` instead or escape the `$`. — gonzo, Mar 08 '16 at 19:02
`$` is a a special character in regex (end of String). You have to escape it — Jens, Mar 08 '16 at 19:06
Firstly in any Linux shell $$ is a special variable, so you would need to use "\$\$" at the very least. Try printing out **argv[0]** before you use it. — Arif Burhan, Mar 08 '16 at 19:08

score -1 · Answer 1 · answered Mar 08 '16 at 19:10

-1

In bash $$ is substituted by the ProcessID a small integer.

answered Mar 08 '16 at 19:10

Arif Burhan

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See also **http://stackoverflow.com/questions/22457166/why-does-echo-return-a-number?lq=1** – Arif Burhan Mar 08 '16 at 19:12

string matches method in java when wanting to compare two dollar signs (not escaping)

1 Answers1