Emacs M-x shell and the overriding of bash keyboard bindings - bash

If I understand correctly, when running bash under M-x shell, Emacs overrides some of the bash keyboard bindings, and can make some bash commands and features not work as in "native bash" (for an example see this thread)
One of the commands that I use frequently in bash is clear-screen (bounded to Ctrl-l by default ).
Is there an easy way of asking Emacs to reproduce the same behavior in shell-mode so that I can clear my bash screen within Emacs?
I know I can always use M-x term to get a real terminal, but I would like to work out a solution for M-x shell
EDIT: When I type C-l C-l, Emacs moves the current line to the top of the window, but as soon as I enter a new command in bash, the window is scrolled again to the original position.
Thanks

Just type M-> to go to the bottom of the buffer (if necessary), then C-l C-l to move the current line to the top of the window. It looks as if you've cleared your screen, but all of the content that would have been erased is still present above the top of the window.
EDIT:
To keep Emacs from scrolling the window as you described, put this in your .emacs file:
(remove-hook 'comint-output-filter-functions
'comint-postoutput-scroll-to-bottom)
I found that behavior irritating as well.

You could re-bind C-l in shell mode to make it function in the manner you want:
(define-key shell-mode-map (kbd "C-l")
(lambda ()
(interactive)
(previous-line)
(end-of-line)
(let ((start (point))
(end (goto-char (point-min))))
(delete-region start end)
(kill-line)
(end-of-buffer))))

Related

How do you terminate a process inside a shell in emacs?

I work a lot in a shell inside emacs (on a Mac). It used to be that, when I typed control-Q control-C, that would kill a process running in the shell. About a year ago, though, that stopped working for some reason; now it has no effect. Anyone know why, or another way of doing this?
I had the same problem using term-mode.
I bound term-interrupt-subjob to my keybinding of choice with:
(add-hook 'term-mode-hook (lambda ()
(define-key term-raw-map (kbd "C-'") 'term-interrupt-subjob)
I am not sure which mode you are using to interact with a shell from Emacs (the inferior shell, Emacs shell, or the terminal emulator). So you might have to modify this a little by replacing term-interrupt-subjob by, for instance, comint-interrupt-subjob and changing the mode hook.
To answer your questions in the comments:
You add the function in your .emacs file. For it to take effect, you need to evaluate it: you can select it and run M-x eval-region or you can restart Emacs.
If you are running M-x shell, you are using shell-mode.
Note that to know which major mode you are using, you can run describe-mode.
Since you are using shell-mode, you want to use add-hook 'shell-mode-hook instead of add-hook 'term-mode-hook and shell-mode-map instead of term-raw-map.
However, in shell-mode, C-c C-c does by default run the command comint-interrupt-subjob. So this should work out of the box as Rorschach said. I am not sure why it isn't working for you.
You can try:
(add-hook 'shell-mode-hook (lambda ()
(define-key shell-mode-map (kbd "C-c C-c") 'comint-interrupt-subjob)
to see if that helps. But this should already be set since it is the default, so it is really unclear whether it will solve your problem.

Command history in emacs shell mode

In the bash shell, I can use the up arrow key to navigate to a previously entered command. But this does not work in emacs shell mode. Is there any way to enable this?
M-p (and M-n for the other direction) will do the trick.
Here is the link to the Emacs manual on the subject.
Add this to your ~/.emacs:
(define-key comint-mode-map (kbd "<up>") 'comint-previous-input)
(define-key comint-mode-map (kbd "<down>") 'comint-next-input)
C-p and C-n and C-r work in (vanilla) bash too, along with some other emacs keys. Very handy.
In Gnu Emacs, the menu for the Shell mode is called "In/Out". (I think it also covers the more general mode called "comint".)

Change the default directory of emacs with 'cocoa emacs'

As explained in here, putting (setq default-directory "~/Desktop/mag" ) in .emacs is supposed to change the default directory.
When I do that with the emacs on my mac, it doesn't work. C-x C-f still shows ~/ not ~/Desktop/mag.
(cd "Users/smcho/Desktop/mag") also gives me this error - Error: No such directory found via CDPATH environment variable
What's wrong with them?
The directory that appears in the prompt for C-x C-f ('find-file') comes from the value of default-directory, which is a buffer-local variable. When you first start Emacs, the initial buffer displayed is the GNU Emacs buffer. That buffer's default-directory is set from the variable command-line-default-directory.
So, try this:
(setq command-line-default-directory "~/Desktop/mag")
The straight-forward answer to your question is:
(setq-default default-directory "~/Desktop/mag")
Reading the documentation for the variable (C-h v default-directory RET) you'll see:
Automatically becomes buffer-local
when set in any fashion. This
variable is safe as a file local
variable if its value satisfies the
predicate `stringp'.
That said, opening a file automatically sets the default-directory to the path of the file...
So, if you always want find-file to start at that directory, you can use this:
(global-set-key (kbd "C-x C-f") 'my-find-file)
(defun my-find-file ()
"force a starting path"
(interactive)
(let ((default-directory "~/scratch/"))
(call-interactively 'find-file)))
This question may be a duplicate of Preventing automatic change of default-directory. Though it's difficult to tell.
In addition to the notes above regarding default-directory, I had to also prevent the emacs splash screen from starting in order to make subsequent commands like dired actually show their buffer when invoked from .emacs on startup:
(setq inhibit-splash-screen t)

Copy/Paste in emacs ansi-term shell

I have configured my emacs to run zsh shell within ansi-term. However, copy/paste no longer works i.e. nothing is getting pasted from kill-ring to the terminal.
Changing the TERM to vt100, or eterm doesn't solve the problem.
Would appreciate any ideas or solution.
To provide context I have configured ansi-term as follows:
(global-set-key "\C-x\C-a" '(lambda ()(interactive)(ansi-term "/bin/zsh")))
(global-set-key "\C-x\ a" '(lambda ()(interactive)(ansi-term "/bin/zsh")))
You may want to simply switch between character mode and line mode while using the terminal. C-c C-j will run term-line-mode, which treats the terminal buffer more like a normal text-buffer in which you can move the cursor and yank text. You can switch back to character mode by running term-char-mode with C-c C-k.
As described in this lovely blog snippet, there's a function, term-paste, in term.el, that does exactly what you want. By default it's bound only to S-insert but the blog's recommended C-c C-y seems like a good suggestion.
ansi-term, in char-mode, takes the ordinary bindings for the terminal emulation. You need a new binding, plus a way to output to ansi-term correctly. I use this:
(defun ash-term-hooks ()
;; dabbrev-expand in term
(define-key term-raw-escape-map "/"
(lambda ()
(interactive)
(let ((beg (point)))
(dabbrev-expand nil)
(kill-region beg (point)))
(term-send-raw-string (substring-no-properties (current-kill 0)))))
;; yank in term (bound to C-c C-y)
(define-key term-raw-escape-map "\C-y"
(lambda ()
(interactive)
(term-send-raw-string (current-kill 0)))))
(add-hook 'term-mode-hook 'ash-term-hooks)
When you do this, C-c C-y will yank. It only does one yank, though, and you can't cycle through your kill-buffer. It's possible to do this, but I haven't implemented it yet.
The above solutions work well for copying text from some buffer to ansi-term, but they aren't able to copy text from ansi-term to another buffer (eg copy a command you just ran to a shell script you're editing). Adding this to my .emacs file solved that problem for me (in Emacs 24.4):
(defun my-term-mode-hook ()
(define-key term-raw-map (kbd "C-y") 'term-paste)
(define-key term-raw-map (kbd "C-k")
(lambda ()
(interactive)
(term-send-raw-string "\C-k")
(kill-line))))
(add-hook 'term-mode-hook 'my-term-mode-hook)
Note that if you want to bind kill/yank to a keystroke that starts with the ansi-term escape characters (by default C-c and C-x), and want this to work in the unlikely event that those change, you can instead define your keystrokes (without the leading escape) to term-raw-escape-map, as is done in user347585's answer.
These other solutions don't work well for me, switching between character mode and line mode causes ansi-term to stop working properly randomly, and setting ansi-term's term-paste to C-c C-y (based on Glyph's link), didn't work the code snippet was for term, not ansi-term:
(eval-after-load "ansi-term"
'(define-key ansi-term-raw-map (kbd "C-c C-y") 'term-paste))
I enabled xterm-mouse-mode, after that I was able to select text using mouse and copy using standard Mac command C button in ansi-term in emacs GUI in Mac OS X,

Creating a Cygwin emacs macro

I have been researching how to get Cygwin to work under emacs. I have it working, but now I want to write a macro that will do the following:
Launch by typing M-x cygwin
Have the script stored in some obvious place (probably my .emacs file)
M-x shell
Rename the buffer to cygwin (or cygwin1, cygwin2, cygwin3, ... if cygwin exists) probably using M-x rename-buffer
M-x ansi-color-for-comint-mode-on
M-x set-buffer-process-coding-system 'undecided-unix 'undecided-unix
Open and run cygwin
It will basically do all of the above steps. I think most of the organization for this little project is done. How do I tie it all together so I can just type M-x cygwin and see a happy new cygwin buffer? What exactly needs to be added to .emacs? Also, where exactly is .emacs in Windows?
I still want the ability to run M-x shell for the windows shell for now. I may also make similar macros for MSYS and ssh'ing to my Linux boxes. How do I get started?
Many questions, here are some answers:
Your .emacs can exist many places, it depends, read here. In short try C-x C-f .emacs, or check the value of the variable 'user-init-file (C-h v user-init-file).
I think the command you want is something along the lines of this:
(require 'comint) ; this does require comint
(defun cygwin ()
"do what i want for cygwin"
(interactive)
(let ((buffer (get-buffer-create (generate-new-buffer-name "cygwin"))))
(pop-to-buffer buffer)
(unless (comint-check-proc buffer)
(apply 'make-comint-in-buffer (buffer-name buffer) buffer "c:/cygwin/Cygwin.bat"
nil
nil)
(ansi-color-for-comint-mode-on)
(set-buffer-process-coding-system 'undecided-unix 'undecided-unix))))
Note: I directly ran the process Cygwin.bat instead of running shell and then starting that batch program. I believe the effect is the same, and more straight forward. I did choose the easy way out for naming the buffer (using 'generate-new-buffer-name) - you'll want to customize to what you want.
You can dump the above command in your .emacs easiest by doing the C-x C-f .emacs and pasting it in the buffer that gets opened up. Save it and restart (or do M-x eval-defun when your cursor is in the body of that command. Then M-x cygwin will run the command.

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