bash循环得到日期目录

 #!/bin/bash
 today=$(date "+%Y%m%d")
 echo 'today is :'${today}
 single_input="raw_data/"
 
 startday=$(date "+%Y%m%d" -d  '90 days ago')
 endday=$(date "+%Y%m%d" -d  '1 days ago')
 
 curday=${startday}
 while (( $curday <= $endday ))
 do
   input=${single_input}${curday}/
     if [ $curday -eq $startday ];then
         all_input=$input
     else
         all_input=$all_input","$input
     fi
     curday=`date -d "+1 day $curday" +%Y%m%d`
 done
 
 echo $all_input