35

When I ssh into another machine with Debian with my account(with sudo permissions), my backspace key generates some awkward symbols on pressing. Also Tab & del keys don't work too.

On the other hand, I also have another account on the same machine & when I ssh through this account, its terminal works perfectly fine. I couldn't figure out why is this happening.

  • Could be a keyboard and text encoding issue, do they all use the same language and keyboard settings? – Kevin Jul 15 '12 at 11:36
  • @Kevin How to check for that? – gopi1410 Jul 15 '12 at 11:58
  • Occasionally mine does it too. But my backspace is acting like my return (Enter) key. @gopi1410, you're not the only one with this issue +1 for the question! – Kevdog777 Aug 14 '12 at 13:57
34

I have seen such problems before.

Take the backspace for example, the remote host expects some character to be used as "erase/backspace" , while you pressing backspace in the terminal , the terminal program will send some character to the remote host, if what the remote host expects diffs with the characters sent by the terminal program, you would encounter this issue. So a quick fix is as below:

  1. run command #stty -a in the remote host, and find what is expected to be an erase code in the output. Say erase=^?.
  2. In the terminal, type Ctrlv and press your backspace. You'll see what code is sent as "erase". Say it is ^H.
  3. In the remote host, run #stty erase ^H.
    (Note: use Ctrlv + Backspace, do not type the ^ manually)

You can fix the Tab issue with the same as above.

  • My backspace character is some special symbol something like an inverted triangle. So its not working – gopi1410 Jul 16 '12 at 10:26
  • 1
    This simple comment is certainly the best solution I have seen to this. It feels like a kludge but it works. – Paulo Matos Aug 13 '15 at 8:08
  • This worked for me! What I don't understand though is why my shell handles backspace as expected, but reading from stdin in my app does not. Doing your suggested change results in backspace working for both. My understanding is that the shell handles stdin buffering, so shouldn't the backspace-handling be the same for both the shell and an app? – Samuel Aug 18 '15 at 22:24
  • 1
    What if no code at all is sent? Ctrlv + backspace produces nothing... – Manfredo Jul 31 '17 at 8:24
29

Beside "stty" solution, you may try the "TERM" solution.

You ssh to your Debian from some terminal (putty, solaris dterm, debain xterm, you-name-it), this termninal announce capabilities (which includes keys such as Backspace and Tab) via TERM environment variable.

So, after ssh to unix host (it doesn't depend debian it or other host) set the TERM variable according to your terminal. Consider you're using bash as shell and vt100 as terminal:

export TERM=vt100

ps: TERM should be announced via ssh automagically, but in some circumstances this magic fails.

  • still doesn't work :( – gopi1410 Aug 14 '12 at 17:49
  • What terminal are you using? And what the value of TERM you have tried? – paul Aug 15 '12 at 6:23
  • I tried vt100. How do I get to know the value of TERM? I tried ssh from cygwin (in windows) to Debian. If there are problems with cygwin, I even tried it from ubuntu terminal, but same problem. – gopi1410 Aug 15 '12 at 12:30
  • Not sure cygwin has good terminal emulation, as far as I know, cygwin just using regular windows console which lacks terminal emulation (may be wrong). From ubuntu all should works just fine. Something wrong with shell or termcap library on debian. Login from Ubuntu and give me output of commands: 1. echo $TERM 2. stty -a – paul Aug 16 '12 at 4:13
  • Well it works fine from my ubuntu machine, wonder why I hadn't verified it before.($TERM was 'xterm' there). So the problem is with cygwin only. Well anyways problem solved if it works with ubuntu :) – gopi1410 Aug 16 '12 at 6:35
15

This is because your default shell is sh, to use bash, just run bash from your shell.

bash

To set bash as your default shell:

chsh -s /bin/bash 

or

sudo chsh -s /bin/bash yourusername
  • 2
    This one fixed it for me. Never even though to look at my login shell! – James Pack Jul 3 '17 at 17:19
  • I am seeing this problem, but my shell is bash. – fraxture Jul 29 at 0:22
6

Your shell may be set to /bin/sh instead of /bin/bash

5

I usually use this to fix any funky character output in my terminal. It resets all the special characters to their default values.

stty sane

From the stty man page:

same as cread -ignbrk brkint -inlcr -igncr icrnl -iutf8 -ixoff -iuclc -ixany imaxbel opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke, all special characters to their default values

  • Backspace is working but tab still fails. – Udo May 3 '17 at 7:12
1

on top of paul's answer, if you want to retain the ability to have colorful output, you can use xterm-88color

echo 'export TERM=xterm-88color' >> ~/.bashrc
source ~/.bashrc
1
# stty -a
speed 38400 baud; rows 34; columns 134; line = 0;
intr = ^C; quit = ^\; erase = ^H; kill = ^U; eof = ^D; eol = <undef>; eol2 = 
<undef>; swtch = <undef>; start = ^Q; stop = ^S;
susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; flush = ^O; min = 1; time = 0;
-parenb -parodd cs8 -hupcl -cstopb cread -clocal -crtscts
-ignbrk brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff - 
iuclc -ixany imaxbel -iutf8
opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl 
echoke

My home key prints a ^[[1~, as per @Derui Si's solution my backspace key is working fine not sure what to do for home key.

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