Bashscripts.org

#!/bin/bash

   set -e

   # use this to recursively search directories
   # will not work if filenames have spaces!
   for FILENAME in $(find . -name "*.mp3"); do

      # test if audio file already has bitrate in filename?
      # use 'sed' to test the three characters before the extension
      # if they are numeric characters or not.
      while [[ `echo $FILENAME | sed 's/^.*\(...\)\..*/\1/'` != *[0-9]* ]]

         do
         
            break
            
         done
   

      if [[ `echo $FILENAME | sed 's/^.*\(...\)\..*/\1/'` != *[0-9]* ]]; then

         BASENAME="${FILENAME%.[^.]*}"
         EXT="${FILENAME:${#BASENAME} + 1}"

      # id3info does NOT read VBR correctly!
      # vbrfix improves bitrate accuraccy but not for every file
         BITRATE=`id3info "$FILENAME" | grep "Bitrate" | cut -c 10-12`

      # this conditional only works for id3info
         if [[ $BITRATE = ??K ]]; then

         # Bitrate is less than 100
            BITRATE=0${BITRATE:0:2}

         fi

         echo $BASENAME.$BITRATE.$EXT

         # uncomment to actually rename files
         #mv -Tv "$FILENAME" "$BASENAME.$BITRATE.$EXT"
   
      fi

   done