libstorj upload files to bucket and overwrite

#!/bin/bash

#Simple Uploader for linux. Place inside libstorj/bin
# The script will create a new directory with randomly generated files, and begin uploading
# Files are automatically removed after uploading.
BUCKET=a882a4d1af7ce8a3bf6674c1
. ~/.storj.
#generates a 16 character unique filename
FILENAME=$(head /dev/urandom | tr -dc A-Za-z0-9 | head -c 16 ; echo '')
#Create Directory to store files in
mkdir upload_files
FILENAME="upload_files/$FILENAME"
logfile="upload_log.log"
echo File name $FILENAME
echo > $logfile

#creates a 1 gig file. Modify to your suiting
#dd if=/dev/urandom of=$FILENAME bs=1024 count=1M
#alternatively, openssl is a faster option
openssl rand -out $FILENAME -base64 $(( 2**30 * 3/4 ))

while :
do
        echo Bucket: $BUCKET
        echo Bucket: $BUCKET >> $logfile
        #change the hash by adding a character
        echo a >> $FILENAME
        storj upload-file -d $BUCKET $FILENAME >> $logfile
        cat $logfile
        FILE_ID=$(tail $logfile | grep -o -w '\w\{24\}')
        echo File ID: $FILE_ID
        storj remove-file $BUCKET $FILE_ID
done