Recursive file manipulation

#!/bin/sh
#
# Notes:
#
# For each flac file in the current directory and its subdirectories,
# convert it to an mp3, importing the flac's tags. If the flac has
# Vorbis tags, use them. Otherwise look for id3v2 tags and use them
# if found. If the flac has no tags, log that fact and skip
# processing the file.
#
# This script traverses directory structures using a mechanism adapted
# from Steve Parker's traverse2.sh script.
#
# I assume that the commands ls, rm, sed, grep, pwd, wc and mkdir exist
# and can be called by those names. But let's make sure this system has
# the necessary third-party software installed, and find the binaries.
# Complain and exit if any one is not found.

METAFLAC=`which metaflac`
FLAC=`which flac`
LAME=`which lame`
ID3INFO=`which id3info`

# Exit if we are missing anything:
if [ -z $METAFLAC ]; then
  echo "metaflac not found! Exiting."
  exit 1
fi

if [ -z $FLAC ]; then
  echo "flac not found! Exiting."
  exit 1
fi

if [ -z $LAME ]; then
  echo "lame not found! Exiting."
  exit 1
fi

if [ -z $ID3INFO ]; then
  echo "id3info not found! Exiting."
  exit 1
fi


# Where to log errors?
LOGFILE=~/flac_err_log

# Where to put the mp3s:
# Create that directory if necessary
MP3ROOT=/media/mp3  # change this to whatever you like
if [ -d $MP3ROOT ]; then
  # then we're OK
else
  mkdir $MP3ROOT
fi

# Parameters for lame - will affect sound quality and file size.
#LAME_PARAMS="-V 0 -h"    # variable bitrate, best quality

# From Steve Parker, only slightly modified:
traverse()
{
  # Traverse a directory

  ls "$1" | while read i
  do
    if [ -d "$1/$i" ]; then
      THISDIR=$1/$i
      # Calling this as a subshell means that when the called
      # function changes directory, it will not affect our
      # current working directory

      if [ -d $MP3ROOT/$THISDIR ]; then
        # directory exists, leave it be
        echo "$MP3ROOT/$THISDIR already exists, not created."
      else
        mkdir $MP3ROOT/$THISDIR
        echo "Copying $THISDIR to $MP3ROOT/$THISDIR"
      fi

      traverse "$1/$i" `expr $2 + 1`
    else
      FILE=$1/$i
      FLACFILE=`echo $FILE | grep -i flac$`

      # Ditch the empty lines:
      if [ -z $FLACFILE ]; then
        # do nothing!
      else
#        echo $FLACFILE

        MP3="$MP3ROOT/$THISDIR/${i%.flac}.mp3"

        # Look for Vorbis tags:
        NUMVTAGS=`$METAFLAC --export-tags-to=- $FLACFILE | wc -l`
        # Create temporary file with tags in shell variable assignment
        # form, depending on whether we found Vorbis or id3v2 tags
        # Any 'slash' characters must be removed now, so they don't cause
        # trouble later. Don't convert quotes yet.

        if [ $NUMVTAGS -gt 0 ]; then    # found Vorbis tags

          # title...
          TITLETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TITLE`
          SLASHFOUND=`echo $TITLETAG | grep \/ | wc -l`
          QUOTEFOUND=`echo $TITLETAG | grep \" | wc -l`

          if [ $SLASHFOUND -gt 0 ]; then    # slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # found slashes and quotes
              TITLETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TITLE |\
                sed 's/\//\-/g' | sed s/\"/\'/ | sed s/\"/\'/`
            else                            # slashes but no quotes
              TITLETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TITLE |\
                sed 's/\//\-/g'`
            fi
          else    # no slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # quotes but no slashes
              TITLETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TITLE |\
              sed s/\"/\'/ | sed s/\"/\'/`
            else                            # no quotes, no slashes
              TITLETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TITLE`
            fi
          fi

          # artist...
          ARTISTTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ARTIST`
          SLASHFOUND=`echo $ARTISTTAG | grep \/ | wc -l`
          QUOTEFOUND=`echo $ARTISTTAG | grep \" | wc -l`

          if [ $SLASHFOUND -gt 0 ]; then    # slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # found slashes and quotes
              ARTISTTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ARTIST |\
                sed 's/\//\-/g' | sed s/\"/\'/ | sed s/\"/\'/`
            else                            # slashes but no quotes
              ARTISTTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ARTIST |\
                sed 's/\//\-/g'`
            fi
          else    # no slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # quotes but no slashes
              ARTISTTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ARTIST |\
              sed s/\"/\'/ | sed s/\"/\'/`
            else                            # no quotes, no slashes
              ARTISTTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ARTIST`
            fi
          fi

          # album...
          ALBUMTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ALBUM`
          SLASHFOUND=`echo $ALBUMTAG | grep \/ | wc -l`
          QUOTEFOUND=`echo $ALBUMTAG | grep \" | wc -l`

          if [ $SLASHFOUND -gt 0 ]; then    # slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # found slashes and quotes
              ALBUMTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ALBUM |\
                sed 's/\//\-/g' | sed s/\"/\'/ | sed s/\"/\'/`
            else                            # slashes but no quotes
              ALBUMTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ALBUM |\
                sed 's/\//\-/g'`
            fi
          else    # no slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # quotes but no slashes
              ALBUMTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ALBUM |\
              sed s/\"/\'/ | sed s/\"/\'/`
            else                            # no quotes, no slashes
              ALBUMTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep ALBUM`
            fi
          fi


          # date, or year...
          DATETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep DATE`
          # track number...
          TRACKNOTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TRACKNUMBER`
          # number of tracks...
          TRACKTOTTAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep TRACKTOTAL`


          # genre... as of this writing, the official tag strings might
          # have spaces...
          # y'know what? Let's skip it. Too much trouble, and usually wrong.
#          GENRETAG=`$METAFLAC --export-tags-to=- $FLACFILE | grep GENRE`
#          SPACEFOUND=`echo $GENRETAG | grep \/ | wc -l`
#          if [ $SPACEFOUND -gt 0 ]; then    # spaces found
#            GENRETAG=`METAFLAC --export-tags-to=- $FLACFILE | grep GENRE |\
#              sed s/\ /\_/g`
#          fi

        else  # No Vorbis tags. Look for id3v2 tags

          # title...
          TITLETAG=`$ID3INFO $FLACFILE | grep TIT2`
          SLASHFOUND=`echo $TITLETAG | grep \/ | wc -l`
          QUOTEFOUND=`echo $TITLETAG | grep \" | wc -l`

          if [ $SLASHFOUND -gt 0 ]; then    # slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # found slashes and quotes
              TITLETAG=`$ID3INFO $FLACFILE | grep TIT2 |\
              sed s/"=== TIT2 (Title\/songname\/content description): "/"TITLE="/ |\
              sed 's/\//\-/g' | sed s/\"/\'/ | sed s/\"/\'/`
            else                            # slashes but no quotes
              TITLETAG=`$ID3INFO $FLACFILE | grep TIT2 |\
              sed s/"=== TIT2 (Title\/songname\/content description): "/"TITLE="/ |\
              sed 's/\//\-/g'`
            fi
          else    # no slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # quotes but no slashes
              TITLETAG=`$ID3INFO $FLACFILE | grep TIT2 |\
              sed s/"=== TIT2 (Title\/songname\/content description): "/"TITLE="/ |\
              sed s/\"/\'/ | sed s/\"/\'/`
            else                            # no quotes, no slashes
              TITLETAG=`$ID3INFO $FLACFILE | grep TIT2 |\
              sed s/"=== TIT2 (Title\/songname\/content description): "/"TITLE="/`
            fi
          fi

          # artist...
          ARTISTTAG=`id3info $FLACFILE | grep TPE1 | \
            sed s/"=== TPE1 (Lead performer(s)\/Soloist(s)): "/"ARTIST="/`
          SLASHFOUND=`echo $ARTISTTAG | grep \/ | wc -l`
          QUOTEFOUND=`echo $ARTISTTAG | grep \" | wc -l`

          if [ $SLASHFOUND -gt 0 ]; then    # slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # found slashes and quotes
              ARTISTTAG=`$ID3INFO $FLACFILE | grep TPE1 |\
              sed s/"=== TPE1 (Lead performer(s)\/Soloist(s)): "/"ARTIST="/ |\
              sed 's/\//\-/g' | sed s/\"/\'/ | sed s/\"/\'/`
            else                            # slashes but no quotes
              ARTISTTAG=`$ID3INFO $FLACFILE | grep TPE1 |\
              sed s/"=== TPE1 (Lead performer(s)\/Soloist(s)): "/"ARTIST="/ |\
              sed 's/\//\-/g'`
            fi
          else    # no slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # quotes but no slashes
              ARTISTTAG=`$ID3INFO $FLACFILE | grep TPE1 |\
              sed s/"=== TPE1 (Lead performer(s)\/Soloist(s)): "/"ARTIST="/ |\
              sed s/\"/\'/ | sed s/\"/\'/`
            else                            # no quotes, no slashes
              ARTISTTAG=`$ID3INFO $FLACFILE | grep TPE1 |\
              sed s/"=== TPE1 (Lead performer(s)\/Soloist(s)): "/"ARTIST="/`
            fi
          fi

          # album...
          ALBUMTAG=`id3info $FLACFILE | grep TALB | \
            sed s/"=== TALB (Album\/Movie\/Show title): "/"ALBUM="/`
          SLASHFOUND=`echo $ALBUMTAG | grep \/ | wc -l`
          QUOTEFOUND=`echo $ALBUMTAG | grep \" | wc -l`

          if [ $SLASHFOUND -gt 0 ]; then    # slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # found slashes and quotes
              ALBUMTAG=`$ID3INFO $FLACFILE | grep TALB |\
              sed s/"=== TALB (Album\/Movie\/Show title): "/"ALBUM="/ |\
              sed 's/\//\-/g' | sed s/\"/\'/ | sed s/\"/\'/`
            else                            # slashes but no quotes
              ALBUMTAG=`$ID3INFO $FLACFILE | grep TALB |\
              sed s/"=== TALB (Album\/Movie\/Show title): "/"ALBUM="/ |\
              sed 's/\//\-/g'`
            fi
          else    # no slashes found
            if [ $QUOTEFOUND -gt 0 ]; then  # quotes but no slashes
              ALBUMTAG=`$ID3INFO $FLACFILE | grep TALB |\
              sed s/"=== TALB (Album\/Movie\/Show title): "/"ALBUM="/ |
              sed s/\"/\'/ | sed s/\"/\'/`
            else                            # no quotes, no slashes
              ALBUMTAG=`$ID3INFO $FLACFILE | grep TALB |\
              sed s/"=== TALB (Album\/Movie\/Show title): "/"ALBUM="/`
            fi
          fi


          # date, or year...
          DATETAG=`$ID3INFO $FLACFILE | grep TYER | \
            sed s/"=== TYER (Year): "/"DATE="/`
          # track number...
          TRACKNOTAG=`$ID3INFO $FLACFILE | grep TRCK | \
            sed s/"=== TRCK (Track number\/Position in set): "/"TRACKNUMBER="/`
          # number of tracks on this album...
          TRACKTOTTAG=`$ID3INFO $FLACFILE | grep TCON | \
            sed s/"=== TCON (Content type): "/"TRACKTOTAL="/ |\
            sed s/\(// | sed s/\)//`
          # skip the genre
        fi

        # Create the temorary file!
        echo $TITLETAG | sed 's/=\(.*\)/="\1"/' > tmpfile
        echo $ARTISTTAG | sed 's/=\(.*\)/="\1"/' >> tmpfile
        echo $ALBUMTAG | sed 's/=\(.*\)/="\1"/' >> tmpfile
        echo $DATETAG | sed 's/=\(.*\)/="\1"/' >> tmpfile
        echo $TRACKNOTAG | sed 's/=\(.*\)/="\1"/' >> tmpfile
        echo $TRACKTOTTAG | sed 's/=\(.*\)/="\1"/' >> tmpfile
#        echo $GENRETAG | sed 's/=\(.*\)/="\1"/' >> tmpfile

        # Make sure tags exist:
        if [ -s tmpfile ]; then  # regular file, nonzero size
          # Include the temporary file:
          . ./tmpfile
          # Delete the temporary file since we're done with it:
          rm tmpfile

#          if [ -z ${GENRE} ]; then  # in some of my files, this field is empty
#            GENRE="Other"
#          fi

# vvv commented during script debugging vvv
          if [ -f $MP3 ]; then
            # mp3 already exists; don't overwrite
            if [ -f $LOGFILE ]; then  # if the log file exists, append
              echo "$THISDIR/$MP3" >> $LOGFILE
            else                      # file does not exist; create
              echo "The following mp3 files already exist and were not created:" \
                > $LOGFILE
              echo "" >> $LOGFILE
              echo "$MP3ROOT/$MP3" >> $LOGFILE
            fi
          else
            echo "Creating ${MP3}..."
            # Create mp3 with tags:
            $FLAC -cd "$FLACFILE" | $LAME -V 0 -h \
            --tt "$TITLE" \
            --tn "$TRACKNUMBER" \
            --ty "$DATE" \
            --ta "$ARTIST" \
            --tl "$ALBUM" \
            --add-id3v2 \
            - "$MP3"
          fi
# ^^^ commented during script debugging ^^^
# vvv use only for debugging vvv
# echo $GENRE
#            --tg "$GENRE" \
# ^^^ use only for debugging ^^^

        else
          if [ -f $LOGFILE ]; then  # if the log file exists, append
            echo "$THISDIR/$FLACFILE" >> $LOGFILE
          else                      # file does not exist; create
            echo "No tags found for the following:" > $LOGFILE
            echo "" >> $LOGFILE
            echo "$THISDIR/$FLACFILE" >> $LOGFILE
          fi
        fi
      fi
    fi
  done
}

traverse . 0