tcp - How to make an Echo server with Bash?

Question

How to write a echo server bash script using tools like nc, echo, xargs, etc capable of simultaneously processing requests from multiple clients each with durable connection?

The best that I've came up so far is

nc -l -p 2000 -c 'xargs -n1 echo'

but it only allows a single connection.

Answer 1

If you use ncat instead of nc your command line works fine with multiple connections but (as you pointed out) without -p.

ncat -l 2000 -k -c 'xargs -n1 echo'

ncat is available at http://nmap.org/ncat/.

P.S. with the original the Hobbit's netcat (nc) the -c flag is not supported.

Update: -k (--keep-open) is now required to handle multiple connections.