FreeBSD command to stop IPFW Firewall

To stop the firewall, issue the command: 
# /etc/rc.d/ipfw stop
To disable firewall remove following line from /etc/rc.conf file: 
firewall_enable="YES"
OR set it as follows:

firewall_enable="NO"

Zero's out the file without breaking pipe

cat /dev/null > filename

Zero's out the file without breaking pipe