I'm in an Ubuntu terminal, and telnet to a server. Now whenever I type 'up', it turns into ^[[A. Other arrow keys also turn into control characters. Is there a way I can run telnet so it understands my arrow keys? This would be a huge help because I'd like to scroll up in my commands history.
It's not telnet that needs to understand the escape sequences your keys produce; it's whatever program you're typing them into at the remote end. Looks like your $TERM environment variable (on the remote system) is not getting set correctly for the terminal you're running telnet in.
It's been a while since I used telnet for logins, but IIRC it doesn't transfer TERM automatically, so you may have to set it yourself. Or, as Mike C suggests, use ssh instead -- that does transfer TERM.
I would either SSH into the server instead of telnet, or use puTTY.
来源：https://stackoverflow.com/questions/7247986/arrow-keys-turn-into-control-characters-in-telnet