Question

3

Bash script won't stay open in background after running through while

rated 0 times [ 3] [ 0] / answers: 1 / hits: 2417 / 2 Years ago, mon, october 17, 2022, 10:09:34

I can't get the following bash script to stay open after the first message is received from NC:

#!/bin/bash

port=3333

nc -l $port | while read msg; do notify-send Alert "$msg"; done

After the first message it exits. I want it to stay open and continue monitoring for new messages from NC.

I know that if I launch nc -l port without the while loop it stays open and I can chat away between the two connections even disconnect from the connected host.

I am sending the message using:

echo 'done' | nc IP port

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byishted

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3 Years ago

answered 2 Years ago scusaper · Accepted Answer

Just add a -k option to nc. Like this:

nc -l $port -k | while read msg; do notify-send Alert "$msg"; done

As seen in man nc:

-k
Forces nc to stay listening for another connection after its current connection is completed. It is an error to use this option without the -l option.