netcardconfig is a bash-script located at /usr/sbin/netcardconfig so you might want to try to understand what it does, if you know enough bash-scripting.
Code:
knoppix@1[knoppix]$ which netcardconfig
/usr/sbin/netcardconfig
knoppix@1[knoppix]$ head -n4 /usr/sbin/netcardconfig
#!/bin/bash
# netcardconfig - A very light-weight text-based network configuration tool.
# (C) Klaus Knopper Nov 2002

knoppix@1[knoppix]$