[support] Nid in URL - How?

Executive Summary: I need help constructing a url that includes the current nid.

Details: I have a footer in a view as follows:

<a href="/node/add/task">Add task.</a> <hr> Input Format: Filtered HTML

I would like a footer which includes a variable (the current nid) as follows (but this does not work).

<a href="/node/add/task&proj_fill[]=$nid">Add related task.</a> <hr> Input Format: Filtered HTML

I have tried a variety of things, but cannot seem to get it to work. For example, this does not seem to work.

<a href="/node/add/task&proj_fill[]=$nid">Add related task.</a> <hr> Input Format: PHP code

Would you help me construct a url that includes the current nid?