vim tmux backspace ^?

Question

I'm having a strange problem:

When sshing into a particular host (from OSX to RHEL5), vim seems to forget how to backspace, but only in a tmux session, ie:

  ssh [email protected]
  vim test

Backspace works fine above.

This doesn't however:

  ssh [email protected]
  tmux
  vim test

Hitting backspace in insert mode produces ^? What could the problem be?

Answer 1

You might need to change your Terminal to send ^h when you type Backspace.

In Terminal's preferences, the setting is part of the profile, so you can set up a dedicated profile for your SSH connection to that RHEL5 system.

Answer 2

You can map the backspace key to what you need, like Kevin said. It looks like you need to map it to ^? (rather than ^H)

To do that, use the following command:

stty erase "^?"

This can be added to your startup scripts (.login or .tcshrc or .bashrc, or other files, depending on which shell you use).

Answer 3

To fix backspace on Apple M1 Pro OSX 12.4 I had to do this

$(brew --prefix)/opt/ncurses/bin/infocmp tmux-256color > ~/tmux-256color.info
tic -xe tmux-256color ~/tmux-256color.info

Issues:

https://github.com/tmux/tmux/issues/1257#issuecomment-581378716

https://gist.github.com/bbqtd/a4ac060d6f6b9ea6fe3aabe735aa9d95

Answer 4

I find giving this command

stty erase Ctrl-V BACKSPACE

works for me. However, I need to do this on every pane.

Answer 5

I made a workaround

1. Make an alias in .alias

   alias emacs(or vi)='stty erase "^H"
   
   emacs'  
   

2. Make a shell script

   # filename tmuxsh
   
   stty ek
   cmd=$(which tmux)      # tmux path
   session=$1
   if [ $# = 0 ]; then
      $cmd ls
      exit 0
   fi
   $cmd has -t $session 2> /dev/null
   if [ $? != 0 ]; then
        $cmd new -s $session
        exit 0
   fi
   $cmd att -t $session
   exit 0
   

Of course, you could make an alias too, alias tm=tmuxsh. then you could use emacs/vi both in tmux or out of tmux well.

Why make an emacs alias in step 1? Because if just use step 2, after quit tmux to normal shell, the emacs/vi will encounter the issue too.

It works well for me.

Answer 6

If you are using xshell like me,try to change Backspace from [Backspace(Ctrl+H)] to [ASCII 127(Ctrl+?)]. In my case, backspace works again in both bash\zsh\tmux+zsh. This problem has nothing to do with $TERM variable.