Selected target files based on file's modification date

! # / bin / bash 
start and due dates # input screening document 
the Read -p " the INPUT firstTime, like 2018-5-6 2:20:31: " FIRST_TIME 
the Read -p " the INPUT secondtime, like 2019-5- 2. 6: 31 is:. 5: " second_time is 
#read -p " INPUT the path of Save: " savepath
 echo $ FIRST_TIME
 echo $ second_time is
 IF [-f File .txt]
 the then 
    Touch  File .txt
 Fi 
date format is converted into the # time stamp, to facilitate comparison 
FIRST_TIME = ` DATE -d " $ FIRST_TIME" +% S` 
second_time =` DATE -d " $ second_time " +% s` 
# recursive function to traverse directory file, filter out all eligible document in that directory
 function the Document () {
 for  File  in ` LS $ 1 `
 do 
    echo $ . 1 " / " $ File 
    IF [-d $ . 1 " / " $ File ]
     the then 
        echo $ . 1 " / " $ File IS A Document
        document $1"/"$file
    else
        aim_time=`ls -lt --full-time $1"/"$file | awk '{ print $6,$7 }'`
        aim_time=`date -d "$aim_time" +%s`
        if [ "$first_time" -lt "$aim_time" ] && [ "$aim_time"-en" $ Second_time " ]
         the then 
            echo $ 1 "/" $ File >> File .txt
         fi 
    fi 
DONE    
} 
# recursive function parameters are to be screened target directory 
the Document $ 1