Audio recording and skip silent period


I am trying to capture the audio output from a radio scanner. This
seems straightforward with 'rec' and 'sox', but I have not found a way
to skip over the silent periods. The output from the radio is silent
most of the time, so it is not very useful to do a continuous
recording. I also need this program to run in the background and create
one file per 24 hours, and then continue on a different file for the
next day etc.. Any help would be appreciated. Thank you.

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