ngrep strives to provide most of GNU grep's common features, applying them
to the network layer. ngrep is a pcap-aware tool that will allow you to
specify extended regular or hexadecimal expressions to match against data
payloads of packets. It currently recognizes TCP, UDP, ICMP, IGMP and Raw
protocols across Ethernet, PPP, SLIP, FDDI, Token Ring, 802.11 and null
interfaces, and understands bpf filter logic in the same fashion as more
common packet sniffing tools, such as tcpdump and snoop.
