dans /etc/cron.hourly/
à rendre executable

#!/bin/bash
if [ ! -e /var/log/souvenirs ]; then
    mkdir /var/log/souvenirs
fi
mv /var/log/messages /var/log/souvenirs/messages"$(date +%D-%H:%M | sed 's/\///g')"
/etc/init.d/syslog-ng stop
pkill syslog-ng
/etc/init.d/syslog-ng start
sleep 5
chmod o+r /var/log/messages