Terminal displays gibberish but working otherwise

Installation
1

Good day. I installed an update today and my system never actually rebooted. I went and checked everything and got it to boot and then tried to log in via Termius and when I logged in, the terminal looked like the below:

image

When I went to the web interface, everything is working fine as far as I can tell. Tried rebooting, same result. Any feedback on this?

2

Hi,

The garbled text looks like control characters which add formatting such as the bold and green colour to give the prompt [core-ssh ~]$ .

Best I can guess, is there was a mis-match between the shell, and the terminal emulator and some character got dropped. Being a greybeard Engineer, this used ot happen over modems and serial terminals, so stty sane ^M got used a lot to reset the shell (CONTROL-M is used instead of the direct ENTER or RETURN keys in case of re-mapping).

For the web shell, ^D (CONTROL-D) will close the session, and hit return to start another.

If this is a persistent issue, the $PROMPT_COMMAND env variable has become corrupted - this is what Bash uses to set the prompt. This is usually set in /etc/bashrc, but on HA, it is in /etc/bash/bashrc

Worst case, remote and reinstall Terminal & SSH. (N.B. The web shell is only visible in “Advanced Mode” users. Profile → turn on Advanced Mode.)

(I was going to suggest checking .bash_profile and .tmux.conf, but there’s not much in there by default so they should be fine. If /etc/bash/bashrc is corrupt, you have larger issues than a bad prompt. BACKUP NOW!)

If this helps, :heart: this post!

1 Like
3

Thank you for your detailed response. I always enjoy learning new stuff. I keep regular backups on my google drive so I’m good there but would like to know, if I wipe the SD card, reinstall from a clean image, and restore from backup, is this error imbedded in the backup and we end up in the same place, or is this a corrupt part of the OS that will be resolved with a fresh installation and restore?

Thanks for your time!

4

I’ve re-read your post, and want to check if my understanding is correct:

  1. Does logging in via the web-shell give the “normal” prompt [core-ssh ~]$ ?
  2. Is Termius a terminal app running on another device, and using this gives corrpuption?
    If so, the issue is less HA, and more the other device terminal app $TERM terminal type.

In the old days, terminals were hardware devices (CRT screen, keyboard, serial interface, later LAN) and worked differently - e.g. VT100 gave different characters than an xterm. Control characters like bold and colours were very likely to use different control codes. Software terminal emulators are the same - try VT100 or xterm or whatever and see if the \e\w\a disappears.

To answer your question directly…
Q: Will a possible corruption be restored as part of a restore?
A: Almost impossible to be sure, as it depends on what is corrupted (e.g. /etc/bash/bashrc is probably HA core, other items may be seen as user-data).

If the web-shell were corrupted, I’d reinstall this first (start with the minimum damage option).

In this case, it might well not be HA at all, but the term type on a client PC emulator…

5

Thanks again for responding.

  1. Wow… That was unexpected… When I logged in via the web-shell (I assume you are referring to the Advanced SSH & Web Terminal in the addon section) it looks fine to me and I get the drawing and a normal looking prompt.

  2. Termius is like PuTTY on steroids, so yes, it is a terminal app. I tried running it on PC, and iOS and had the gibberish. I also tried PuTTY and had the same gibberish. Its weird becuase I have always used Termius to SSH into HA and never had an issue. Now, suddenly, I can only use the web-shell. Any suggestions? I would agree with you on Termius being the issue if PuTTY didnt exhibit the same behavior.

Thanks again for your time.

6

This confirms your issue is more likely to be the $TERM type on the client.

Try fixing the $TERM type on the client (terminal type being emulated - experiment).

I set up a test from a Win10 box using Putty 64-bit and SSH’ing in to HA. The prompt worked fine, and gave:

[core-ssh ~]$ echo $TERM
xterm

Default install of PuTTY 64b, Answerback to ^E: = PuTTY.

After adding a ssh-rsa key to Authorized Keys, I can also SSH in from a Linux box fine ($TERM=xterm-256color).

Try reinstalling PuTTY? Try reinstalling the HA Terminal & SSH Add-On?

If this helps, :heart: this post!