我在一个文件夹中有大约200k个文件，我想根据出生时间（创建时间）来组织它们。我写了下面的脚本，但太慢了。我想改进一下。我该怎么做？

# !/usr/bin/env bash
echo Input directory is $1
input_directory=$1
## Find those files that are older than a month
inputfiles=$(hadoop fs -ls  $input_directory | sed '1d;s/  */ /g' | cut -d\  -f8)
for filename in $inputfiles
  do
   echo processing $filename
   hadoop fs -test -d  $filename
   lastcommand=$?
   if [ "$lastcommand" == "1" ];then
        year=$(date -d "`hadoop fs -stat $filename`" +%Y)
        month=$(date -d "`hadoop fs -stat $filename`" +%m)
        hadoop fs -test -d $input_directory/$year-$month
        lastcommand2=$?
        [[ "$lastcommand2" == "1" ]] && hadoop fs -mkdir -p $input_directory/$year-$month;
        hadoop fs -mv $filename $input_directory/$year-$month/
    else
        echo not a file
   fi
  done