>>
>> I'm looking for a simple tool where I can point it at an http audio
>> stream, define a number of seconds to detect silence and exit with a
>> non-zero status if silence is detected. It seems like this should be
>> easy but I've been search high and low for such a utility and nothing
>> simple exists. Unfortunately I'm not much of a developer, but this
>> doesn't seem like it would be that difficult. Maybe it's harder than
>> I think, hence no tool that I can find.
>
>
https://github.com/x42/silan may do the job. It prints ranges or silence
> in a file or stream (incl. mp3,aac,wma,ogg,m4a,.. decoding and http,
> rtmp stream support thanks to libav/ffmpeg). It is used by airtime
> (sourcefabric's radio) to highlight silent ranges.
>
> silan -t 0.1 -s -60d "http://mp2.somafm.com:9016" \
> | grep -quiet "Sound Off" \
> && echo " do something"