Basics
Listen on TCP port
nc -nl 1234
Specify on which IP address to listen on
nc -nl 127.0.0.1 1234
Sending files
Send a file to the remote host
Receiver
nc -nlv PORT > /path/to/file
Sender
nc -nv IP PORT < /path/to/file
Host and download file from the server
Bind nc
with content of the file on local port
nc -lp PORT < /path/to/file
Then grab a file from other host
nc HOST PORT > output.file