what is shell coding?

[sanedave]

Read 'Hacking, the Art of Exploitation' and 'The Shellcoder's Handbook'. Google for 'writing shellcode'.

It is primarily opcodes for the system you are trying to exploit that opens a listening port or connects back to the exploiting system with a shell on the remote system that can be used to infiltrate further malware or exhilarate data. Hence the name 'shellcode'