Script to redeem automatically books from `https://www.packtpub.com/packt/offers/free-learning` using bash and cronjob

packtpub_redeem.sh

#!/bin/bash
#==INSTRUCTIONS
# - Add EMAIL and PASS infomation
# - Replace script path with your path `/home/USER/scripts/` in the script
# - Check your machine timezone `date +"%Z %z"` output ex: UTC +0000
# - patckpub.com is UTC +0000, find the best hour for you to use in the crontab
# - Execute `crontab -e`
# - Add `0 1 * * * /bin/sh /home/USER/scripts/packtpub_redeem.sh > /home/USER/scripts/packtpub_redeem.out` , this mean everyday 1am
# - Restart Service `sudo service cron reload` (optional, crontab -e, will reload)
# - Add Permission `chmod 755 /home/USER/scripts/packtpub_redeem.sh`
#==
COOKIE="cookie.txt"
EMAIL=""
PASS=""

#Change dir to script folder
mkdir -p /home/${USER}/scripts/
cd /home/${USER}/scripts/

#Login and store Cookie
curl --silent -X POST -c ${COOKIE} \
    -d "mail=${EMAIL}&password=${PASS}"  \
    https://www.packtpub.com/api/user/login > login.json

#Get Claim URL
PACKT_CLAIM_URL=$(
curl --silent  https://www.packtpub.com/packt/offers/free-learning | \
    grep  freelearning-claim | \
    sed 's/\t//g' | \
    awk '{print "https://www.packtpub.com"$2}' | \
    sed -e 's/href\=\"//g' -e 's/.$//g'
)

#Claim book using the Cookies from previous login and the extracted Claim URL
#https://www.packtpub.com/freelearning-claim/XXX/YYY
curl --silent -L -X GET -b ${COOKIE} ${PACKT_CLAIM_URL} > output.html