I'm currently trying to make a template for future virtual hosts. To minimize the amount of editing required i am using $server_name in some parts of the template.

For example:
server_name example.com
access_log /var/log/www/$server_name-access combined;
error_log /var/log/www/$server_name-error error;

While it works great for access_log directive(logfile is named example.com-access), error log file name is, actually $server_name-error.
I'm running nginx 1.0.6