Recording 48Khz, raw, piping through a five second buffer, encode to flac and dump on a USB stick:

  arecord -D hw:1,0 -v --fatal-errors --buffer-size=192000 -f dat -t raw | dd bs=480000 | flac --endian=little --channels=2 --bps=16 --sample-rate=48000 --sign=signed -o /mnt/usbstick/`date '+%s'`.flac -

Gotta love Linux :)