nc (netcat) hangs, waiting for more data, in UDP mode.

Solution 1:

I ended up fixing the problem by switching to socat:

while read line; do
    printf "folder.counter:value|1c" | socat -t 0 - UDP:$host:$port
done

Solution 2:

You can specify 0 as a timeout value to -w, so it won't wait at all.

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Solution 3:

adding -v option solved my issue. The reason I am not sure.

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Solution 4:

I had same issue; solved it using the -c option:

-c, --close                close connection on EOF from stdin

so something like

while read line; do
    printf "folder.counter:value|1c" | nc -cu $host $port
done

Yeah, does not really make sense to "close" a udp-connection - but that ended up working.