How to see error info and debug info from Apache server?

Nowadays when running WAMP or MAMP (or the default web server on a Mac), whenever 开发者_如何学Gothere is error from the CGI file (such as Ruby or PHP), the error message is not shown (and no line number either). Is there a way to run the web server in a shell so that any error message is shown?

The one I am trying to show is on a Mac's built-in web server. (maybe it is a little different in other MAMP or WAMP platforms)

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You can find the errors of CGI scripts in /var/log/apache2/error_log for the default web server on apache.

You can view realtime results using :

tail -f /var/log/apache2/error_log