Fish is an alternative Shell. I find that it has much better tab completion.

FAQs

https://fishshell.com/docs/current/faq.html

Setting an environment variable

set -x key value

• -x or --export
  • Make value an "Environment variable"
• -e or --erase
  • Erases the specified shell variable

Checking the value of an environment variable

echo $VARNAME

Dump all environment variables env