Ported from: https://gist.github.com/gatekeepr/97d6244dc074280b32f505443fbd7fe6

gumroad_grabber.sh

#! /bin/bash
# Bash gumroad downloader based on a python script from user gatekeepr:
# https://gist.github.com/gatekeepr/97d6244dc074280b32f505443fbd7fe6
# Easily extendable with GNU Parallel! (if you have the download capacity :)
# TODO: Could use a fancy bar or download counter...

url="https://gumroad.com/d/a795646b9ddc4a496c6cab5e3fa179b5"
cookies_path="./cookies.txt"
download_path="./"

# Replaces /d/ in url to /r/
url="${url/'\/d\/'/'\/r\/'}"

# Finds the json between 'DownloadPage/FileList" data-react-props="' and '" data-hydrate="t" data-react-cache-id='
elements=$(curl -c /cookies.txt -b ./cookies.txt $url -L -Ss | grep -oP '(?<=DownloadPage/FileList" data-react-props=").*(?=" data-hydrate="t" data-react-cache-id=)')

# Converts all the &quot; to actual quotes:
elements="${elements//'&quot;'/'"'}"

# Uses jq to build arrays for our files
names=($(echo $elements | jq -r ".files[].file_name | @sh"))
urls=($(echo $elements | jq -r ".files[].url"))
extensions=($(echo $elements | jq -r ".files[].extension"))

ITER=0
for url in ${urls[@]}; do
        name=$(cut -d "'" -f2 <<< ${names[$ITER]}) # Remove single quotes
        file_name="$download_path/$name.${extensions[$ITER]}"
        curl $url \
                --continue-at - --location \
                -c $cookies_path -b $cookies_path \
                -o $file_name
         ((ITER++))
done

No wonder, it's old. It can stay just to refer folks to your comment and as reference for a future bash implementation.

Anyway... Thank you for your wonderful project!!