simple patch to the jack_capture example client, that implements silence detection and splitting of output files.
jrec2 can call hooks (invoke 3rd party software) upon detecting silence or audio. It include an optional random-playback control script that was used in an installation to record voice and if it detects silence plays back random snippets of previously recorded material.
pure-data might have been a wiser choice to maintain this; but besides the learning experience this c-code is very easy to deploy and keep-alive.
reqires: libsoundfile, jack-audio-connection-kit
gcc -l jack -lsndfile jrec-v2.c -o jrec2