Re: Specifying shells for remote ob-shell sessions?

[Tim Cross]

David Dynerman <emperordali@block-party.net> writes:

> Dear Org Mode Friends,
>
> I’m having some trouble getting the shell I want to run on remote hosts in
> session ob-shell blocks - it seems that no matter what shell I specify, 
> session
> blocks will always run /bin/sh. I’m not sure if this is an org or tramp
> configuration issue on my end, or a bug in org.
>
> I’m pasting a snippet that reproduces the behavior in emacs -Q below. Does
> anyone have an inkling if this is a bug, or, alternatively, suggestions for 
> how
> I can run remote ob-shell sessions with the shell of my choice?
>
> Thank you,
> David
>
> #+BEGIN_SRC emacs-lisp                                                        
>                                   
>   (require 'ob-shell)                                                         
>                                   
>   (emacs-version)                                                             
>                                   
> #+END_SRC                                                                     
>                                   
>
>
> #+RESULTS:
> : GNU Emacs 27.2 (build 1, x86_64-apple-darwin17.7.0, Carbon Version 158 
> AppKit 1561.6)                         
> :  of 2021-05-20                                                              
>                                   
>
> #+BEGIN_SRC emacs-lisp                                                        
>                                   
>   (org-version)                                                               
>                                   
> #+END_SRC                                                                     
>                                   
>
>
> #+RESULTS:
> : 9.4.4                                                                       
>                                   
>
> #+BEGIN_SRC zsh :dir /ssh:remote-host:/home/ubuntu                            
>                            
>     echo $0
> #+END_SRC                                                                     
>                                   
>
>
> #+RESULTS:
> : zsh                                                                         
>                                   
>
> #+BEGIN_SRC zsh :dir /ssh:remote-host:/home/ubuntu :session foobar            
>                            
> echo $0
> #+END_SRC                                                                     
>                                   
>
> #+RESULTS:
> |           |
> | $ /bin/sh |


This is just some wild guess work, so may be completely wrong ....

I don't think it is a bug. The ob-shell library doesn't really know
anything about remote - the fact you can execute things remotely is just
part of the underlying Emacs tramp support.

As far as I know, the shell you get in the remote login is determined by
the remote host i.e. in the /etc/passwd file of the remote user account
(for login shells) and /bin/sh if ssh is just being called to execute a
command. In your case, because your calling echo $0 it is executed with
/bin/sh

 I would start with tramp and try to configure it to execute commands
 using zsh. The ob-shell library isn't really aware of 'remote' - it is
 just calling tramp based on the path you provide, which is why I think
 tramp is a good place to start. If this cannot be easily done, look at the ssh 
manual and
 see if you can do this via a ~/.ssh/rc file on the remote host.

If you cannot find a way to configure tramp, perhaps try working out how
to just execute commands over ssh in a specific shell, like zsh. I
suspect once you work out how to do this with plain ssh, you may see a
way to configure tramp to do the same.

A final solution would be to just add a call to zsh in your source block
before the rest of what you want to run. 


-- 
Tim Cross