Netcat Echo Service – Send Text, Read Reply, and Exit

echonetcat

I would like to use netcat to send a piece of text to the echo service on my server, get the reply then exit, so that I know the connection is still good. so far I've tried:

 echo 'test' | netcat server 7

this way netcat would wait for more input rather than exit.

How can I make netcat exit after getting reply from the echo service?

Best Answer

Just tried - slightly different behaviour between netcat-openbsd and netcat-traditional ( ubuntu 16.4). The OpenBSD variant does what you expect, while with the netcat-traditional I need to add the -q 1 to avoid waiting for more input.

echo 'test' | netcat -q 1 server 7

Related Solutions

Half-close netcat connection

The comment by @meuh suggested using socat for this purpose. Based on that I've successfully used

some command | socat -t30 - TCP:localhost:1234

To transfer data including EOF and then still receive the response.

How to get espeak to continuously speak stdout piped from netcat

I tried netcat -lk on my pi jessie with the 3 different versions of netcat, but they either dont support -k, or the server ending up in a busy loop after the first connection:

$ strace nc -l -k -p 7777 </dev/null | espeak --stdout >/dev/null
poll([{fd=0, events=POLLIN}, {fd=-1}], 2, -1) = 1 ([{fd=0, revents=POLLNVAL}])

I suggest you use socat which worked for me. Here's the equivalent line:

socat -u TCP4-LISTEN:7777,reuseaddr,fork - | espeak

Best Answer

Related Solutions

Half-close netcat connection

How to get espeak to continuously speak stdout piped from netcat

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