I'm trying to learn to use shell-switcher in
emacs (https://github.com/DamienCassou/shell-switcher). On my
local machine it works exactly as described. On a remote machine
that I access through ssh emacs seems to ignore the C- prefix in the
shell-switcher default keybinding of C-'.
On my local machine, C-h k C-' yields:
C-' runs the command shell-switcher-switch-buffer, which is an
interactive autoloaded compiled Lisp function in
`shell-switcher.el'.
But on the remote machine it yields:
' runs the command self-insert-command, which is an interactive
built-in function in `C source code'.
It is bound to many ordinary text characters.
Other C- bindings work as expected.
Could anyone suggest how I might further debug this to figure out
where along the [local shell--ssh--remote shell--remote emacs] chain my C- is getting intercepted?
Related
I'm using WSL (WSL2 in fact) for a few days and I'm a bit confuse about keyboard combination redirection and/or interception.
I have to say that my favorite tool to edit text is emacs, that use a lot of keyword combinations.
My stack is this one :
Under windows, I run Windows terminal (WT.exe)
In this terminal I open a tab which (afaik magically) is a shell on a linux subsystem. This subsystem is a Debian
In this shell I run emacs.
The whole thing looks like that :
At this point, when I enter a key combination, it may be passed to emacs, or it may be intercepted/interpreted by any other layer of the stack.
For instance :
ctrl-e is interpreted by emacs : it move the caret to the end of file
ctrl-z is interpreted by wsl2 (afaik) : it pauses emacs as a background job
ctrl-tab is interpreted by windows terminal : it changes tab
alt-f4 is interpreted by windows : it closes windows terminal
And some of them are a mystery for me. For instance ctrl-_ (ctrl underscore), which is very useful on default emacs configuration, is not interpreted by emacs. It is translated at some point as "delete". In this configuration typing "delete" or "ctrl-_" is the very same thing : it removes the first character before the caret.
Very specifically and synthetically stated, my question would be : "How do I configure this stack to make emacs receive ctrl-_ ?"
Of course more generally, I really would like to know, how each layer works and is parameterized. For instance, is there a configuration file for WT and/or WSL2, that says which combination are forwarded, which one are interpreted and which one are ignored.
Additional Data :
If I run WSL2 through WT, but don't start emacs, ctrl-_ is also interpreted as "delete"
If I run another type of "tab" in WT, like cmd.exe or powershell, ctrl-_ is not interpreted as "delete". I don't know if it is interpreted at all
If I run WSL2 without WT, Ctrl-_ is not interpreted at all.
I didn't found any mention of ctrl-_ in WT config shortcuts.
Additional Data :
I tried to run following python program in both stacks : WT/WSL and WT/CMD.EXE
import keyboard
while(True):
c = keyboard.read_key()
print(c)
On WT/CMD.EXE, the output is :
ctrl
_
_
ctrl
Which means it receive the keyboard info.
On WT/WSL2, it fails to run. Apparently "keyboard" is not compatible with WSL2. But this is not the question here.
A useful tool for debugging input on linux is showkey -a. You can use that to help debug what keys the client application is receiving. If you press a key and it doesn't display anything in the output, then there's a good chance it's being intercepted by the Terminal.
There's probably an open issue for this on the Terminal repo. #8458 looks similar.
is there a configuration file for WT and/or WSL2, that says which combination are forwarded, which one are interpreted and which one are ignored.
defaults.json is the file that contains all the keybindings that the Windows Terminal binds by default.
What WSL does is more complicated. IIRC, the inputrc file on linux is used readline (for bash, etc) to specify how certain keys are handled by the shell. But then there are also keys configured in stty that control other parts of the TTY interface. That part I understand less.
alt-f4 is interpreted by windows : it closes windows terminal
FWIW That's actually a application-level keybinding. The Terminal handles that key manually, so that people can optionally disable it. See defaults.json
I connect to the remote machine with ssh user#192.168.1.5. When I need to open a file in the remote machine I do, e.g.,
emacs /usr/share/nginx/html/index.html
and that opens the index.html file in the shell. I noticed that some emacs commands work but others do not work. For instance, C-w does not work; M-< does not work. How can I fix this, and what is the best way to work with emacs and ssh?
I found this question but it made me more confused.
I generally prefer opening remote files from a local Emacs instance.
While running Emacs on your local machine, opening a remote file over ssh is not much different than opening any other file besides a slightly different syntax.
For ssh, you can type C-x C-f. Now, in the minubuffer you want to type /ssh:user#host:/path/to/file (Note that tab completion will work once you start typing a path. Also note the leading / character). See the full docs here.
In your example, that would be:
C-x C-f /ssh:user#192.168.1.5:/usr/share/nginx/html/index.html
Now you can edit remote files over ssh in Emacs while using your local configuration and any installed packages, etc...
Just to add to the answer above, you can write shortcuts for machines that you use
frequently:
(defun connect-remote ()
(interactive)
(dired "/user#192.168.1.5:/"))
This will open a dired buffer on a remote machine. You can navigate this buffer
as you would a local one.
If you have set up ssh keys for the remote machine, you don't even have to enter the password.
If you have a bunch of remote machines, you can give some recognizable name
to each function, e.g. connect-cupcake, connect-kitkat and use smex package for completion.
And to add to #abo-abo's post about "shortcuts" --
Use Emacs bookmarks. Just create bookmarks normally, when you visit a remote file or directory. Then just use C-x r b to jump to a remote bookmark, whose name you provide (with completion).
If you use Bookmark+ then remote bookmarks are highlighted specially in the *Bookmark List*, so you can recognize them more easily. And remote bookmarks that must be accessed by su or sudo (root) are highlighted differently.
If you use Dired+ then you can also quickly bookmark multiple remote files or directories, by visiting their containing remote directory in Dired, marking them, and hitting C-x b. No need to give the bookmarks names; they are named after the files. Even if you never use those bookmarks for navigating to the remote files, you can use them with Bookmark+ tags to organize the files and thus operate on subsets of them.
If you use Icicles then whenever you use a command to jump to a bookmark, you can narrow the completion candidates to those that are remote by hitting C-M-# during completion.
The original poster expressed interest in opening remote files as the root user. This can be done with the command:
C-x C-f /ssh:you#remotehost|sudo:remotehost:/path/to/file RET
More documentation can be found here: https://www.emacswiki.org/emacs/TrampMode#toc14
A Simple Answer that focuses on the remote machine:
If I plan to do all my emacs work on the remote machine, I use
ssh -X username#hostname
and then run emacs in the remote session, displaying back on my local machine. It's an old question but I wanted to throw this in for completeness. Granted there are some xhost / X config issues but in many networks this will work right off the bat!
SSH mode for emacs is what you're looking for.
Once you have it set up you just run
M-x ssh RET hostname RET
Then it prompts you for your password twice (once for the command line, once for loading files).
For the most part you can treat it like any other shell (non-interactive and a few minor differences, but that's it).
It keeps track of which directory you're in, so when you want to open a file from the directory you're looking at it automatically starts in the right directory and you just need to enter in the file name.
Emacs Wiki has more info too.
I'm trying to get set up with SLIME on a Windows 7 box, but running M-x slime gives me the error
Spawning child process: invalid argument
I have inferior-lisp-program set to "C:\\Program Files\\ccl\\wx86cl.exe" (which is factually correct, and running (comint-run inferior-lisp-program) gives me a working CCL prompt), and the slime directory added to my 'load-path.
What am I doing wrong?
EDIT: Tried loading up the same environment through the Windows edition of lispbox, and it runs SLIME fine. I'd prefer not to use that one because it packages an older Emacs, CCL and SLIME than I want.
The message you received means that there's a high chance that there was a syntax problem with the command given to shell. This would be caused by having characters in the file name, which can be interpreted as doing something special. So, it looks like Emacs was trying to call C:\\Program "program" with an argument Files\\ccl\\wx86cl.exe.
There are several ways to address the error:
There has to be an escaping function, something like:
(shell-quote-argument "C:\\Program Files\\ccl\\wx86cl.exe")
But since you cannot affect how the file name is passed to the function which creates the process, this isn't going to work.
You can move the program you want to call to a directory with "safe" name.
You can move the executable to be on the system path (%PATH% variable in Windows) - through changing environment variables and appending the directory with the executable to it.
One more option is to add the directory with the executable to exec-path variable in Emacs. This variable holds a list of all directories looked up for programs to run, if you just call a program by name, rather then by full path. This also (at least for me) makes my .emacs file easier to port between different systems.
I am trying to run Emacs on a guest system (Ubuntu 12.04)
inside a Windows 8 command console.
This is done through vagrant + Virtual box.
It looks like this,
Guest system : Ubuntu 12.04
Host system : Windows 8
Environment : Virtual Box + Vagrant
Emacs works fine except I can not set mark on text (C-SPC).
I supposed there is some kind conflict with the key binding.
So I tried and added this to init.el,
(global-set-key (kbd "C-8") 'set-mark-command)
It doesn't work either.
Would someone please advice me?
If you're running Emacs in a terminal, then C-SPC and C-8 are unlikely to send what you want them to.
Use C-h c C-SPC to ask Emacs what it's seeing.
Try using C-# instead.
FYI, I found the Cygwin X server excellent for running GUI Emacs in a Windows-hosted VM. With GUI Emacs you can use many more key combinations than a terminal emulator will permit.
If you try that, start the server with startxwin rather than startx (the former enables the X server's windows to appear as regular Windows windows), and then connect from an xterm with ssh -X or ssh -Y (see the man page) to connect with X11 forwarding.
Thanks a lot for the hint.
I finally figured out what the problem really is.
From the answer #phils, this link clarifies the problem.
Why does Ctrl+. not work when I bind it to a command in Emacs?
In my case, all C-[any other key] bindings work, except for the set-mark-command.
I found a workaround.
By adding the following code to .emacs.d\init.el I can use F8 to set mark now.
(global-set-key [f8] (quote set-mark-command))
It is still confusing why in other command, Ctrl+key bindings works.
I tried to open a remote file via Emacs via Tramp.
(require 'tramp)
(setq tramp-default-method "ssh")
I get a message from Emacs
Tramp: Waiting for prompts from remote shell
Emacs hung and did not respond to any action after that
Emacs was installed on Windows; the remote file was on a Linux machine.
If the account you're connecting to uses some weird fancy shell prompt, then there is a good chance that this is what makes tramp trip.
Log in as root, then enter
PS1="> "
(that's a normal, standard shell (ZSH, BASH, younameit) prompt, one that tramp will understand)
then switch to the user account, and launch emacs -q (to make sure that your .emacs is not causing this mess) and try to C-x C-f /sudo:root#localhost:/etc/hosts and see what's what.
You can (not recommended) also customize the regexp that defines what tramp expects :
M-x customize-variable RET tramp-terminal-prompt-regexp
My approach :
Make sure the variable tramp-terminal-type is set to "dumb"
M-x customize-variable RET tramp-terminal-type
Test that in your .*shrc and serve the correct prompt :
case "$TERM" in
"dumb")
PS1="> "
;;
xterm*|rxvt*|eterm*|screen*)
PS1="my fancy multi-line \n prompt > "
;;
*)
PS1="> "
;;
esac
Your Windows ssh client is the key here, and the 'ssh' Tramp method is almost certainly wrong.
If you're using Cygwin, then you need to use the 'sshx' method, and you probably need to use ssh-agent to handle authentication. Details are here:
Using tramp with EmacsW32 and cygwin, possible?
I imagine the same applies to any stand-alone ssh client which does not require a full Cygwin installation, but does use the Cygwin DLLs. (I mention this, because I'm pretty sure I remember seeing such a thing.)
If you're using PuTTY then you want the 'plink' method, as Alex Ott pointed out. If the Wiki doesn't suffice, a search here will probably turn up solutions for configuring that approach.
Other alternatives I can suggest are:
Use the Cygwin-native Emacs. That will be slower than NTEmacs, but Tramp seems to work well with the 'ssh' method, and password-prompting works as well.
Host a Linux VM on your Windows box, and run Emacs on that. That's a fairly large hoop to jump through, but it's my preferred way of using Tramp when working in Windows.
Well, this is a defect of tramp.
The real solution is to prevent loading .bashrc when tramp is used. (because now it is PS1, but it can be PATH, or any other thing that your .bashrc will do that will displease tramp...).
This can be done by asking ssh to set an environment variable, and testing it in .bashrc:
Add this to ~/.emacs:
(require 'tramp-sh nil t)
(setf tramp-ssh-controlmaster-options (concat "-o SendEnv TRAMP=yes " tramp-ssh-controlmaster-options))
and that at the beginning of ~/.bashrc:
if [ ! -z ${TRAMP-x} ] ; then
return
fi
Another default of tramp is that it doesn't have a variable to pass random arguments to the ssh command, we have to piggy-back on tramp-ssh-controlmaster-options.
Had you checked Emacs wiki for solution? ssh is in PATH? It's also recommended to use plink on MS Windows - see section "Inline methods" in Tramp documentation
If the problem is your fancy custom prompt in the remote shell, an easy workaround is to add to your .bashrc or equivalent:
if [[ $TERM == "dumb" ]]; then
export PS1="$ "
fi
After you define your PS1.
Note: the credit goes to ChasingLogic as this is their suggestion in this thread.
By the way -- if You need tramp to sudo -- You can actually sudo without tramp using sudoedit.
Currently I'm using this bash function:
erf () { SUDO_EDITOR="emacsclient -a emacs" sudoedit $#; }