AKA

Netcat into the given domain an port. Trying a bunch of different commands it appears that none of them do what you'd expect.

Running alias shows that there are different aliases for commands which let you open files. Instead of trying to figure them all out I converted the flag.txt file to base64 with base64 flag.txt. Then it was a simple matter of copying the output and decoding it (I used cyberchef).