Re: Saving/Recalling Shell Commands History?

[Peter Dyballa]

Am 21.08.2006 um 23:32 schrieb Kevin Rodgers:

> So leave it commented out, and put this in your ~/.emacs file:
>
> (add-hook 'shell-mode-hook
>           (lambda ()
>             (setq comint-input-ring-file-name ; buffer-local
>                   (expand-file-name "history" desktop-dirname))))

The code above works, but it only works for GNU Emacs. The shell  
never gets knowledge of this!

I think the meaning of comint-input-ring-file-name is to let GNU  
Emacs know directly, for whatever reason or use, what the shell's  
history file is. Maybe it's useful in dumb shells that cannot provide  
their own history, maybe it's useful in TRAMP, i.e. working in a  
remote shell.

For my purpose I extended your hook to make the shell know where the  
actual history file of the Emacs *shell* buffer is. Since I want to  
separate the different Emacs versions I am using I have created an  
intermediate and temporary file, ~/.emacs_tcsh-init, which contains a  
line that tells the shell which file to use for a history. For tcsh  
the file ~/.emacs_tcsh is executed in *shell* buffer. So  
~/.emacs_tcsh needs to be extended by one line that loads the  
intermediate file – and removes it!

Here is my extended hook:

        (add-hook 'shell-mode-hook
          (lambda ()
            (setq comint-input-ring-file-name
                  (expand-file-name "history" desktop-dirname))
            (setq histfile_cmd (format
                            "echo \"set histfile = %s\" > .emacs_tcsh-init"
                            comint-input-ring-file-name))
            (shell-command histfile_cmd)
        ))

~/.emacs_tcsh-init will have a line like:

        set histfile = <some path name>

The extended version of ~/.emacs_tcsh has two more lines:

        sleep 1
	if (-e ~/.emacs_tcsh-init) source ~/.emacs_tcsh-init && rm  
~/.emacs_tcsh-init

The sleep is needed, otherwise the file's removal fails with an error  
message in *shell*. One cannot feel this one more second in GNU  
Emacs's start-up.


For bash the history file is addressed by the environment variable  
$HISTFILE. It's probably OK to use the syntax

        HISTFILE=<some path name>

without 'export.' The syntax for the ~/.emacs_bash file would be:

	if [ -e ~/.emacs_bash-init ]; then . ~/.emacs_bash-init && rm  
~/.emacs_bash-init; fi


There is one more disadvantage: an empty buffer *Shell Command  
Output* is created because of executing (shell-command  
histfile_cmd) ... Could be a kill-buffer in the hook removes it!

--
Greetings

  Pete

The day Microsoft makes something that doesn't suck
is the day they start selling vacuum cleaners.
                                    Ernest Jan Plugge