Export from the devices table to stdout or append a json file.

usage: kismet_log_devices_to_filebeat_json [-h] --in INFILE [--out OUTFILE]
                                           [--start-time STARTTIME]
                                           [--min-signal MINSIGNAL]

optional arguments:
-h, --help               show this help message and exit
--in INFILE              Input (.kismet) file
--out OUTFILE            Output filename (optional) for appending. If unspecified,
                         each record will be printed to stdout, one record per line,
                         ideal for piping into filebeat.
--start-time STARTTIME   Only list devices seen after given time
--min-signal MINSIGNAL   Only list devices with a best signal higher than min-signal