http://www.tldp.org/LDP/abs/html/index.html

file_size=$(stat -c%s "$FILENAME")

read -p "Press [Enter] key to start backup..."

Extracting File Name with extension and without extension given full file path

filewithpath=/home/name/path/subpath/etc/abc.txt
filename=$(basename $filewithpath)
filenoext=${filename%%.*}

filename will have abc.txt

filenoext will have abc