netcat

Connectivity testing
`nc $host $port`	establish connection to port (telnet-style)
`nc -u $host $port`	establish connection to port (telnet-style)
`nc -vz $host $port`	check if port is open
`nc -vz $host $minport-$maxport`	check if port is open
`nc -l $port`	listen on a port
Communication/data transfer
`nc -l $port \| tar -xzf -`	Listen on a port and pipe somewhere
`tar -czf - $files \| nc $host $port`	Pipe to netcat and send