Hi, sorry for the late reply. In case it helps, or helps someone in the future, you need to make sure to pipe the output from wget to sha256sum:
wget --quiet -O - url.to.bitadr.org.html | sha256sum
(notice the " | sha256sum" after what you had above). This takes the whole file and sends it to be inputted into the sha256sum program, which will hash the file and give you the output (checksum).
Hey well written article! I had a quick question. I now have a number of alt coins on 2 different exchanges - Cryptopia and Kucoin. Do you know the best way to keep these alt coints safe. For obvious reasons now every wallet will be able to store these alt coins so not quite sure what to do. Also, if you purchase alt coints and you take them out of the exchange platform (cryptopia kucoin) will the value still go up if you transfer to a wallet? I hope that makes sense and appreciate your help!