Some basic Unix/Linux network commands for Troubleshoot

Troubleshooting or just need a quick refresher on some basic and advanced Unix Linux network related commands?

ifconfig - configure a network interface (setup)
route - show / manipulate the IP routing table
ping, ping6 - send ICMP ECHO_REQUEST to network hosts
netstat - Print network connections, routing tables, interface statistics, masquerade connections, and multicast memberships

tcpdump - dump traffic on a network
tcpslice - extract pieces of and/or glue together tcpdump files

traceroute - print the route packets trace to network host
tracepath, tracepath6 - traces path to a network host discovering MTU along this path
iwconfig - configure a wireless network interface
iwlist - Get more detailed wireless information from a wireless interface
wpa_supplicant - Wi-Fi Protected Access client and IEEE 802.1X supplicant
wpa_supplicant.conf [wpa_supplicant] - configuration file for wpa_supplicant
ipcalc - perform simple manipulation of IP addresses
nc - arbitrary TCP and UDP connections and listens
snort - open source network intrusion detection system
ettercap - A multipurpose sniffer/content filter for man in the middle attacks
ethereal - Interactively dump and analyze network traffic