Determine audio file overall bit rate in Kbps.

get_bitrate.sh

# sudo apt-get install mediainfo
# input is a file or a glob mask (first file is taken in this case)
# output is one decimal number - bitrate of a file. Zero if file not found.
get_bitrate() {
 F="${1}"
 FOUND=$(compgen -G "${F}" | head -n1)
 if [ -z "${FOUND}" ] 
  then
   echo 0
 else
   echo $(mediainfo "${FOUND}" | grep "Overall bit rate  " | tail -n1 | sed 's/.*: \(.*\) .*/\1/' | sed 's/[^0-9\\.]//g')
 fi
}