How can I append to a file using dd? On Linux systems, I can append to a system file like this:

echo "# New data" | sudo dd of=/etc/config_file conv=notrunc oflag=append


But the dd command under OS X doesn't have the oflag option. Is this possible under OS X?

Notes:


I need root access.
I'm not asking for alternative solutions, I'm asking if dd has the capability.
You can seek to the end of the target file:

sudo echo "# New data" |
    dd of=/etc/config_file conv=notrunc bs=1 seek=$(stat -f "%z" /etc/config_file)