id3 - Searching for a song with Zenity in Bash -

i've got problem bash project. it's simple songs id3 search app. there bug when find song, $song doesn't concatenate $found. works until print them below separator line. going wrong?

title="" found=""  while [ 1 -eq 1 ];     output=$(zenity --forms --title="search" --text="search id3" --separator="," --add-entry="song title")     if [ $? -eq 0 ];         title=`echo $output | cut -d "," -f 1`         find . -name "*.mp3" -print0 | while read -d $'\0' song                     echo "$song"             if [ "$title" ];                 if id3info "$song" | grep "=== tit2" | grep -q "$title";                     found="${found}${song}"                     echo "found song: $song"                     echo "all: $found"                 fi             fi         done         echo "================================="         echo "$found"         echo "$found" | zenity --text-info --height 500 --width 500 --title "songs"     else         exit     fi done