Creating differential backups with hard links and rsync

Creating differential backups with hard links and rsync:


From above:
backup@backup_server> DAY2=`date +%Y%m%d%H%M%S` 

backup@backup_server> cp -al /var/backups/$DAY1 /var/backups/$DAY2 

backup@backup_server> rsync -av -e ssh --delete earl@192.168.1.20:/home/earl/ /var/backups/$DAY2/

Find IP addresses with a lot of open connections:
netstat -atun | awk '{print $5}' | cut -d: -f1 | sed -e '/^$/d' |sort | uniq -c | sort -n

Source:
http://www.cyberciti.biz/tips/netstat-command-tutorial-examples.html