Challenge 1: Confirm a Running Instance — Possible Solution
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127.0.0.1:6379> PING

WHY THIS WORKS AS AN ANSWER
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PING is Redis's simplest possible connectivity check — it doesn't
touch any data, it just asks the server "are you there and responsive?"

The response that confirms success is:

PONG

Receiving PONG back confirms two things at once: the redis-cli client
successfully established a connection to the server, and the server is
actually running and able to respond to commands — not just that a
port happens to be open. If the server were down or unreachable,
redis-cli would report a connection error instead of ever getting to
print PONG.