!7

sclass NumberOfMics > DynBigNumber {
  void start {
    doEvery(5.0, r actualUpdate);
  }
  
  void actualUpdate {
    temp enter();
    S text = apacheCommonsExec_backtick("arecord -l");
    setValue(or(last(regexpFirstGroups("\\bcard (\\d+):", text)), "?"));
  }
}