recursive() {
  for d in *; do
    if [ -d "$d" ]; then
      (cd -- "$d" && recursive)
    fi
  dir=`pwd`
  pattern="*.xyz"
file_count=$(find $dir -name $pattern | wc -l)
if [[ $file_count -gt 0 ]]; then
    echo "Match found. Going to execute a command"
    #execute command
fi
  done
}

(cd /target; recursive)