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I recently discovered the neat kitty as some aspects of the themes I'm using under ZSH don't render quite right under Xfce Terminal but do under kitty.

Unfortunately I've hit a snag when it comes to using tmux on SSH connections, if SSH from my desktop/server (running Gentoo) to any of my Raspberry Pis (running Arch Linux ARM) or my VPS (also running Arch Linux) and start a Tmux session I'm informed....

open terminal failed: missing or unsuitable terminal: xterm-kitty

However, I've a laptop which is also running Arch and if I SSH to it from my desktop/server and start an SSH session there are no problems, and vice versa, SSHing from laptop to desktop/server and Tmux runs fine.

I should add that I can run Tmux sessions when SSHing to the Raspberry Pis/VPS's that are running Arch Linux if its under an Xfce Terminal.

Any ideas as to how I can investigate or solve this such that Tmux sessions work everywhere?

Evan Carroll
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slackline
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3 Answers3

21

If you receive error messages such as "Terminal unknown, missing or unsuitable terminal" upon logging in, this means the server does not recognize your terminal.

The correct solution is to install the client terminal's terminfo file on the server. This tells console programs on the server how to correctly interact with your terminal. You can get info about current terminfo using infocmp and then find out which package owns it.

If you cannot install it normally, you can copy your terminfo to your home directory on the server:

$ ssh myserver mkdir -p  ~/.terminfo/${TERM:0:1}
$ scp /usr/share/terminfo/${TERM:0:1}/$TERM myserver:~/.terminfo/${TERM:0:1}/

After logging in and out from the server the problem should be fixed.

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    Brilliant, thank your for the clear and succinct explanation and solution. To ease maintenance I opted to install kitty on the remote servers that didn't already have it installed, although I if I ever need to save space I'll adopt the `/.terminfo` mirroring and add it to my dotfiles. – slackline Sep 22 '18 at 11:05
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    Minor update as I've been unable to install kitty on servers at work you solution has worked perfectly. Thank you again. – slackline Feb 12 '19 at 10:46
  • This creates the file /home/user/.terminfo/x/xterm-kitty but that does not seem to impact tmux generating this error or behavior. – Evan Carroll Apr 04 '19 at 15:29
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The accepted answer from @user88036 is a good explanation and a nice generic solution. I recently discovered in the Kitty docs they have a nice utility using their CLI tool. From the docs

This happens because the kitty terminfo files are not available on the server. You can ssh in using the following command which will automatically copy the terminfo files to the server:

kitty +kitten ssh myserver

https://sw.kovidgoyal.net/kitty/faq.html#i-get-errors-about-the-terminal-being-unknown-or-opening-the-terminal-failing-when-sshing-into-a-different-computer

40four
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0

If you're connected to a machine where it's not possible to install terminfo files, you can set the TERM environment variable to to something that is supported by the machine — profiles that are pretty much compatible with kitty, in decreasing order of preference, include

  • xterm-256color
  • xterm-color
  • xterm
  • vt102

If you want the login shell (e.g. bash) on the remote machine to pick up the correct terminal, you should export it into the environment before running ssh. If you don't care because you're only going to run tmux, you can set it after. Naturally, you will lose some of the cool features of kitty, but in a case where you can't install terminfo and having the basic features takes preference, it can still be handy.

hobbs
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    This is an error [called out in the XTerm _FAQ_](http://invisible-island.net/xterm/xterm.faq.html#other_versions-id). One _should not_ just blithely go around using the `xterm-*` entries with things that are not XTerm, and the `vt102` entry describes an actual DEC VT 102 which [almost all terminal emulators _do not_ in fact emulate](http://invisible-island.net/xterm/xterm.faq.html#what_is_vt220). The very premise of this answer is wrong, too. The questioner _can_ install terminfo files, because terminfo (as built on Arch) _also_ looks in one's home directory. – JdeBP Sep 22 '18 at 15:00
  • what cool features of kitty do you lose? – iconoclast Sep 27 '21 at 21:52