backtrace.join($/) How is this code working

I am amazed at how this code is working.

backtrace.join($/)

what does that dollar sign mean and what’s that slash before that. Full code at http://snippets.dzone.com/posts/show/2427

I am amazed at how this code is working.

backtrace.join($/)

what does that dollar sign mean and what's that slash before that. Full code
at http://snippets.dzone.com/posts/show/2427

backtrace is a method that returns....

Returns any backtrace associated with the exception. The backtrace is an array of strings, each containing either ``filename:lineNo: in `method or ``filename:lineNo.

join takes that array and joins it using $/ which I believe is the default line separator (usually defaults to \n, but maybe \r\n, or something else entirely if you've set it to that).

-philip