this is obsolete doc -- see http://doc.nethence.com/ instead

Log rotation techniques 

Logrotate 

Configure /etc/logrotate.d/daemonname. In example for apache, 

/var/log/httpd/*log {

        monthly

        nomissingok

        sharedscripts

        postrotate

                /sbin/service httpd reload > /dev/null 2>/dev/null || true

        endscript

}

Newsyslog 

NetBSD uses newsyslog, much nicer. 

Self-made script 

In example each hour, 

mv web11.tgz web12.tgz

mv web10.tgz web11.tgz

mv web9.tgz  web10.tgz

mv web8.tgz  web9.tgz

mv web7.tgz  web8.tgz

mv web6.tgz  web7.tgz

mv web5.tgz  web6.tgz

mv web4.tgz  web5.tgz

mv web3.tgz  web4.tgz

mv web2.tgz  web3.tgz

mv web1.tgz  web2.tgz

mv web.tgz   web1.tgz

mv web.log   web.old

/usr/sbin/apachectl graceful

sleep 300

tar cvfz web.tgz web.old

Crontab 

The right way, 

crontab -e

in example (monthly), 

0 0 1 * * /usr/bin/newsyslog 

The wrong way, 

cat /etc/cron.daily/logrotate

in example, 

#!/bin/sh

/usr/sbin/logrotate /etc/logrotate.conf

EXITVALUE=$?

if [ $EXITVALUE != 0 ]; then

    /usr/bin/logger -t logrotate "ALERT exited abnormally with [$EXITVALUE]"

fi

exit 0