setterm -blength 0

Sets the bell length to zero for all applications

ipconfig getpacket en0

According to the manual page for ipconfig, this command appears to be unique to Mac OS X.

The command will display a bunch of useful info, including:

server_identifier (ip): That's your DHCP server's IP address.
yiaddr: Your machine's IP address.
chaddr: Your machine's MAC address.
domain_name_server: Your domain name server(s).

<property file="${antutil.includes}/${os.name}-${os.arch}.properties" />

Use to include properties per OS

Most useful for providing a consistent uid on machines accessing an NFS mount:

$ sudo find . -xdev -user <old-uid> -print -exec chown <new-uid> {} \;