Odd cgi behaviour - perl

Question

I am getting some very annoying behaviour from my perl cgi scripts running under apache.
I get referer information added on the end of simple print statements, and it's driving me nuts.
[Sun Feb 20 21:34:47 2011] [error] [client xx] ruid: 48, referer: http://www.x.com/
[Sun Feb 20 21:34:47 2011] [error] [client xx] euid: 48, referer: http://www.x.com/
[Sun Feb 20 21:34:47 2011] [error] [client xx] test, referer: http://www.x.com/
[Sun Feb 20 21:34:47 2011] [error] [client xx] Premature end of script headers: test.cgi, referer: http://www.x.com/
This only seems to happen when the url is reached by navigating from another page (hence having a referer yes). The above apache log output was produced with the below incredibly simple depo script:
#!/usr/bin/perl -w
use strict;
use warnings;
use CGI;
my $q = CGI->new;
print STDERR "ruid: $<\n";
print STDERR "euid: $>\n";
print STDERR "test\n";
Anyone seen this before? It feels like an apache setting i need to turn off.
Thanks
Matt

Answer 1

Take a look at your apache config files (httpd.conf and friends) and find the CustomLog directive which is used by your error log to see which LogFormat it uses, then modify that LogFormat (or create a new one) to remove %{Referer} from the list of fields to include in the log messages. (And don't forget to reload the apache config after changing it, of course.)