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https://github.com/akermu/emacs-libvterm

Emacs libvterm integration
https://github.com/akermu/emacs-libvterm

emacs libvterm terminal terminal-emulator

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Emacs libvterm integration

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README 

        
[![MELPA](https://melpa.org/packages/vterm-badge.svg)](https://melpa.org/#/vterm)



# Introduction



Emacs-libvterm (_vterm_) is fully-fledged terminal emulator inside GNU Emacs

based on [libvterm](https://github.com/neovim/libvterm), a C library. As a

result of using compiled code (instead of elisp), emacs-libvterm is fully

capable, fast, and it can seamlessly handle large outputs.



## Warning



This package is in active development and, while being stable enough to be used

as a daily-driver, it is currently in **alpha** stage. This means that

occasionally the public interface will change (for example names of options or

functions). A list of recent breaking changes is in

[appendix](#breaking-changes). Moreover, emacs-libvterm deals directly with some

low-level operations, hence, bugs can lead to segmentation faults and crashes.

If that happens, please [report the

problem](https://github.com/akermu/emacs-libvterm/issues/new).



## Given that eshell, shell, and (ansi-)term are Emacs built-in, why should I use vterm?



The short answer is: unparalleled performance and compatibility with standard

command-line tools.



For the long answer, let us discuss the differences between `eshell`, `shell`,

`term` and `vterm`:

- `eshell`: it is a shell completely implemented in Emacs Lisp. It is

  well-integrated in Emacs and it runs on Windows. It does not support command line

  tools that require terminal manipulation capabilities (e.g., `ncdu`, `nmtui`,

  ...).

- `shell`: it interfaces with a standard shell (e.g., `bash`). It reads an input

  from Emacs, sends it to the shell, and reports back the output from the shell.

  As such, like `eshell`, it does not support interactive commands, especially

  those that directly handle how the output should be displayed (e.g., `htop`).

- `term`: it is a terminal emulator written in elisp. `term` runs a shell

  (similarly to other terminal emulators like Gnome Terminal) and programs can

  directly manipulate the output using escape codes. Hence, many interactive

  applications (like the one aforementioned) work with `term`. However, `term`

  and `ansi-term` do not implement all the escapes codes needed, so some

  programs do not work properly. Moreover, `term` has inferior performance

  compared to standalone terminals, especially with large bursts of output.

- `vterm`: like `term` it is a terminal emulator. Unlike `term`, the core of

  `vterm` is an external library written in C, `libvterm`. For this reason,

  `vterm` outperforms `term` and has a nearly universal compatibility with

  terminal applications.



Vterm is not for you if you are using Windows, or if you cannot set up Emacs

with support for modules. Otherwise, you should try vterm, as it provides a

superior terminal experience in Emacs.



Using `vterm` is like using Gnome Terminal inside Emacs: Vterm is fully-featured

and fast, but is not as well integrated in Emacs as `eshell` (yet), so some of

the editing keybinding you are used to using may not work. For example,

`evil-mode` is currently not supported (though, users can enable VI emulation in

their shells). This is because keys are sent directly to the shell. We are

constantly working to improve this.



# Installation



## Requirements



Before installing emacs-libvterm, you need to make sure you have installed

 1. GNU Emacs (>= 25.1) with [module

    support](https://www.gnu.org/software/emacs/manual/html_node/elisp/Dynamic-Modules.html).

    You can check that, by verifying that `module-file-suffix` is not `nil`.

 2. cmake (>= 3.11)

 3. libtool-bin (related issues:

    [#66](https://github.com/akermu/emacs-libvterm/issues/66)

    [#85](https://github.com/akermu/emacs-libvterm/issues/85#issuecomment-491845136))

 4. OPTIONAL: [libvterm](https://github.com/Sbozzolo/libvterm-mirror.git) (>= 0.2). This

    library can be found in the official repositories of most distributions

    (e.g., Arch, Debian, Fedora, Gentoo, openSUSE, Ubuntu). Typical names are

    `libvterm` (Arch, Fedora, Gentoo, openSUSE), or `libvterm-dev` (Debian,

    Ubuntu). If not available, `libvterm` will be downloaded during the

    compilation process. Some distributions (e.g. Ubuntu < 20.04, Debian < 11)

    have versions of `libvterm` that are too old. If you find compilation errors

    related to `VTERM_COLOR`, you should not use your system libvterm. See

    [FAQ](#frequently-asked-questions-and-problems) for more details.



## From MELPA



`vterm` is available on [MELPA](https://melpa.org/), and it can be installed as

a normal package. If the requirements are satisfied (mainly, Emacs was built

with support for modules), `vterm` will compile the module the first time it is

run. This is the recommended way to install `vterm`.



`vterm` can be install from MELPA with `use-package` by adding the following

lines to your `init.el`:



```elisp

(use-package vterm

    :ensure t)

```



To take full advantage of the capabilities of `vterm`, you should configure your

shell too. Read about this in the section [shell-side

configuration](#shell-side-configuration).



## Manual installation



Clone the repository:



```sh

git clone https://github.com/akermu/emacs-libvterm.git

```



By default, vterm will try to find if libvterm is installed. If it is not found,

emacs-libvterm will download the latest version available of libvterm (from

[here](https://github.com/neovim/libvterm)), compile it, and use it. If you

always want to use the vendored version as opposed to the one on you system, set

`USE_SYSTEM_LIBVTERM` to `no`. To do this, change `cmake ..` with `cmake

-DUSE_SYSTEM_LIBVTERM=no ..` in the following instructions.



Build the module with:



```sh

cd emacs-libvterm

mkdir -p build

cd build

cmake ..

make

```



And add this to your `init.el`:



```elisp

(add-to-list 'load-path "path/to/emacs-libvterm")

(require 'vterm)

```



Or, with `use-package`:



```elisp

(use-package vterm

  :load-path  "path/to/emacs-libvterm/")

```



## vterm and Ubuntu

### 20.04

Using `vterm` on Ubuntu requires additional steps. The latest LTS version

(20.04) ships without CMake installed and Emacs27 is not yet available from Ubuntu's package repository.



The basic steps for getting vterm to work on Ubuntu 20.04 are:

* Ensure Emacs27 is installed

* Install cmake, libtool, and libtool-bin



There are a few options for installing Emacs27 on Ubuntu 20.04:

* Compile Emacs27 from source

* Install Emacs27 from Snap

* Install Emacs27 from Kevin Kelley's PPA



In any case, if you have an older Emacs version you will need to purge it before proceeding:



#### Purge Emacs



```sh

sudo apt --purge remove emacs

sudo apt autoremove

```



#### Installing Emacs27 from Kevin Kelley PPA



```sh

sudo add-apt-repository ppa:kelleyk/emacs

sudo apt install emacs27

```



##### If you get an error about emacs27_common during the install process:



```sh

Errors were encountered while processing:

 /tmp/apt-dpkg-install-RVK8CA/064-emacs27-common_27.1~1.git86d8d76aa3-kk2+20.04_all.deb

```



run



```sh

sudo apt --purge remove emacs-common

sudo apt --fix-broken install

```



#### Installing Emacs27 from Snap

I hesitate to include SNAP here, because I ran into a number of GTK Theme parsing errors, and Fontconfig errors when I tested it, and reverted to installing from Kevin Kelley's PPA. YMMV



```sh

sudo snap install emacs --classic

```



#### Install CMake and Libtool

In Ubuntu 20.04 CMake (v3.16.3-1ubuntu1) and Libtool can be installed with



```sh

sudo apt install cmake

sudo apt install libtool

sudo apt install libtool-bin

```



### 18.04



Using `vterm` on Ubuntu 18.04 requires additional steps.

18.04 ships with a version of CMake that is too old for `vterm` and GNU

Emacs is not compiled with support for dynamical module loading.



It is possible to install GNU Emacs with module support from Kevin Kelley's PPA.

The binary in Ubuntu Emacs Lisp PPA is currently broken and leads to segmentation faults

(see [#185](https://github.com/akermu/emacs-libvterm/issues/185#issuecomment-562237077)).

In case Emacs is already on the system, you need to purge it before proceeding

with the following commands.



```sh

sudo add-apt-repository ppa:kelleyk/emacs

sudo apt update

sudo apt-get install emacs26

```



A way to install a recent version of CMake (>= 3.11) is with linuxbrew.



```sh

brew install cmake

```



In some cases, `/bin/sh` needs to be relinked to `/bin/bash` for the compilation

to work (see,

[#216](https://github.com/akermu/emacs-libvterm/issues/216#issuecomment-575934593)).



Pull requests to improve support for Ubuntu are welcome (e.g., simplifying the

installation).



Some releases of Ubuntu (e.g., 18.04) ship with a old version of libvterm that

can lead to compilation errors. If you have this problem, see the

[FAQ](#frequently-asked-questions-and-problems) for a solution.



## GNU Guix



`vterm` and its dependencies are available in GNU Guix as

[emacs-vterm](https://guix.gnu.org/packages/emacs-vterm-0-1.7d7381f/).

The package can be installed with `guix package -i emacs-vterm`.



## Shell-side configuration



Some of the most useful features in `vterm` (e.g., [directory-tracking and

prompt-tracking](#directory-tracking-and-prompt-tracking) or [message

passing](#message-passing)) require shell-side configurations. The main goal of

these additional functions is to enable the shell to send information to `vterm`

via properly escaped sequences. A function that helps in this task,

`vterm_printf`, is defined below. This function is widely used throughout this

readme.



For `bash` or `zsh`, put this in your `.zshrc` or `.bashrc`



```sh

vterm_printf() {

    if [ -n "$TMUX" ] \

        && { [ "${TERM%%-*}" = "tmux" ] \

            || [ "${TERM%%-*}" = "screen" ]; }; then

        # Tell tmux to pass the escape sequences through

        printf "\ePtmux;\e\e]%s\007\e\\" "$1"

    elif [ "${TERM%%-*}" = "screen" ]; then

        # GNU screen (screen, screen-256color, screen-256color-bce)

        printf "\eP\e]%s\007\e\\" "$1"

    else

        printf "\e]%s\e\\" "$1"

    fi

}

```



This works also for `dash`.



For `fish` put this in your `~/.config/fish/config.fish`:



```fish

function vterm_printf;

    if begin; [  -n "$TMUX" ]  ; and  string match -q -r "screen|tmux" "$TERM"; end

        # tell tmux to pass the escape sequences through

        printf "\ePtmux;\e\e]%s\007\e\\" "$argv"

    else if string match -q -- "screen*" "$TERM"

        # GNU screen (screen, screen-256color, screen-256color-bce)

        printf "\eP\e]%s\007\e\\" "$argv"

    else

        printf "\e]%s\e\\" "$argv"

    end

end

```



# Debugging and testing



If you have successfully built the module, you can test it by executing the

following command in the `build` directory:



```sh

make run

```



# Usage



## `vterm`



Open a terminal in the current window.



## `vterm-other-window`



Open a terminal in another window.



## `vterm-copy-mode`



When you enable `vterm-copy-mode`, the terminal buffer behaves like a normal

`read-only` text buffer: you can search, copy text, etc. The default keybinding

to toggle `vterm-copy-mode` is `C-c C-t`. When a region is selected, it is

possible to copy the text and leave `vterm-copy-mode` with the enter key.



If no region is selected when the enter key is pressed it will copy the current

line from start to end. If `vterm-copy-exclude-prompt` is true it will skip

the prompt and not include it in the copy.



## `vterm-clear-scrollback`



`vterm-clear-scrollback` does exactly what the name suggests: it clears the

current buffer from the data that it is not currently visible.

`vterm-clear-scrollback` is bound to `C-c C-l`. This function is typically used

with the `clear` function provided by the shell to clear both screen and

scrollback. In order to achieve this behavior, you need to add a new shell alias.



For `zsh`, put this in your `.zshrc`:



```zsh

if [[ "$INSIDE_EMACS" = 'vterm' ]]; then

    alias clear='vterm_printf "51;Evterm-clear-scrollback";tput clear'

fi

```



For `bash`, put this in your `.bashrc`:



```bash

if [ "$INSIDE_EMACS" = 'vterm' ]; then

    clear() {

        vterm_printf "51;Evterm-clear-scrollback";

        tput clear;

    }

fi

```



For `fish`:



```fish

if [ "$INSIDE_EMACS" = 'vterm' ]

    function clear

        vterm_printf "51;Evterm-clear-scrollback";

        tput clear;

    end

end

```



These aliases take advantage of the fact that `vterm` can execute `elisp`

commands, as explained below.



If it possible to automatically clear the scrollback when the screen is cleared

by setting the variable `vterm-clear-scrollback-when-clearing`: When

`vterm-clear-scrollback-when-clearing` is non nil, `C-l` clears both the screen

and the scrollback. When is nil, `C-l` only clears the screen. The opposite

behavior can be achieved by using the universal prefix (i.e., calling `C-u C-l`).



# Customization



## `vterm-shell`



Shell to run in a new vterm. It defaults to `$SHELL`.



## `vterm-environment`



to add more environment variables there is the custom vterm-environment which has

a similar format than the internal Emacs variable process-environment.

You can check the documentation with C-h v process-environment for more details.



## `vterm-term-environment-variable`



Value for the `TERM` environment variable. It defaults to `xterm-256color`. If

[eterm-256color](https://github.com/dieggsy/eterm-256color) is installed,

setting `vterm-term-environment-variable` to `eterm-color` improves the

rendering of colors in some systems.



## `vterm-kill-buffer-on-exit`



If set to `t`, buffers are killed when the associated process is terminated (for

example, by logging out the shell). Keeping buffers around it is useful if you

need to copy or manipulate the content.



## `vterm-module-cmake-args`



Compilation flags and arguments to be given to CMake when compiling the module.

This string is directly passed to CMake, so it uses the same syntax. At the

moment, it main use is for compiling vterm using the system libvterm instead of

the one downloaded from GitHub. You can find all the arguments and flags

available with `cmake -LA` in the build directory.



## `vterm-copy-exclude-prompt`



Controls whether or not to exclude the prompt when copying a line in

`vterm-copy-mode`. Using the universal prefix before calling

`vterm-copy-mode-done` will invert the value for that call, allowing you to

temporarily override the setting. When a prompt is not found, the whole line is

copied.



## `vterm-use-vterm-prompt-detection-method`



The variable `vterm-use-vterm-prompt-detection-method` determines whether to use

the vterm prompt tracking, if false it use the regexp in

`vterm-copy-prompt-regexp` to search for the prompt.



## `vterm-enable-manipulate-selection-data-by-osc52`



Vterm support copy text to Emacs kill ring and system clipboard by using OSC 52.

See https://invisible-island.net/xterm/ctlseqs/ctlseqs.html for more info about OSC 52.

For example: send 'blabla' to kill ring: printf "\033]52;c;$(printf "%s" "blabla" | base64)\a"



tmux can share its copy buffer to terminals by supporting osc52(like iterm2 xterm),

you can enable this feature for tmux by :

set -g set-clipboard on         #osc 52 copy paste share with iterm

set -ga terminal-overrides ',xterm*:XT:Ms=\E]52;%p1%s;%p2%s\007'

set -ga terminal-overrides ',screen*:XT:Ms=\E]52;%p1%s;%p2%s\007'



The clipboard querying/clearing functionality offered by OSC 52 is not implemented here,

And for security reason, this feature is disabled by default."



This feature need the new way of handling strings with a struct `VTermStringFragment`

in libvterm. You'd better compile emacs-libvterm with `cmake -DUSE_SYSTEM_LIBVTERM=no ..`.

If you don't do that, when  the content you want to copied is too long, it would be truncated

by bug of libvterm.



## `vterm-buffer-name-string`



When `vterm-buffer-name-string` is not nil, vterm renames automatically its own

buffers with `vterm-buffer-name-string`. This string can contain the character

`%s`, which is substituted with the _title_ (as defined by the shell, see

below). A possible value for `vterm-buffer-name-string` is `vterm %s`, according

to which all the vterm buffers will be named "vterm TITLE".



This requires some shell-side configuration to print the title. For example to

set the name "HOSTNAME:PWD", use can you the following:



For `zsh`,



```zsh

autoload -U add-zsh-hook

add-zsh-hook -Uz chpwd (){ print -Pn "\e]2;%m:%2~\a" }

```



For `bash`,



```bash

PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND; }"'echo -ne "\033]0;${HOSTNAME}:${PWD}\007"'

```



For `fish`,



```fish

function fish_title

    hostname

    echo ":"

    prompt_pwd

end

```



See [zsh and bash](http://tldp.org/HOWTO/Xterm-Title-4.html) and [fish

documentations](https://fishshell.com/docs/current/#programmable-title).



## `vterm-always-compile-module`



Vterm needs `vterm-module` to work. This can be compiled externally, or `vterm`

will ask the user whether to build the module when `vterm` is first called. To

avoid this question and always compile the module, set

`vterm-always-compile-module` to `t`.



## `vterm-copy-mode-remove-fake-newlines`



When not-nil fake newlines are removed on entering copy mode.

vterm inserts fake-newlines purely for rendering. When using

`vterm-copy-mode` these are in conflict with many emacs functions

like isearch-forward. if this varialbe is not-nil the

fake-newlines are removed on entering copy-mode and re-inserted

on leaving copy mode. Also truncate-lines is set to t on entering

copy-mode and set to nil on leaving.



## `vterm-tramp-shells`



The shell that gets run in the vterm for tramp.



This has to be a list of pairs of the format:

`(TRAMP-METHOD SHELL)`



The `TRAMP-METHOD` is a method string as used by tramp (e.g., `"ssh"`).

Use t as `TRAMP-METHOD` to specify a default shell for all methods.

Specific methods always take precedence over `t`.



Set SHELL to `'login-shell` to use the user's login shell on the remote host.

The login-shell detection currently works for POSIX-compliant remote hosts that

have the `getent` command (regular GNU/Linux distros, *BSDs, but not MacOS X

unfortunately).

You can specify an additional second `SHELL` command as a fallback

that is used when the login-shell detection fails, e.g.,

`'(("ssh" login-shell "/bin/bash") ...)`

If no second `SHELL` command is specified with `'login-shell`, vterm will

fall back to tramp's shell.



Examples:

- Usee the default login shell for all methods, except for docker.

  `'((t login-shell) ("docker" "/bin/sh"))`

- Use the default login shell for ssh and scp, fall back to "/bin/bash".

  Use tramp's default shell for all other methods.

  `'(("ssh" login-shell "/bin/bash") ("scp" login-shell "/bin/bash"))`



## Keybindings



If you want a key to be sent to the terminal, bind it to `vterm--self-insert`,

or remove it from `vterm-mode-map`. By default, `vterm.el` binds most of the

`C-` and `M-` keys, `` through `` and some special keys

like `` and ``. Sending a keyboard interrupt is bound to `C-c

C-c`.



In order to send a keypress that is already recognized by Emacs, such as `C-g`,

use the interactive function `vterm-send-next-key`. This can be bound to a key

in the `vterm-mode-map` like `C-q`, in which case pressing `C-q C-g` will send a

`C-g` key to the terminal, and so on for other modified keys:



```elisp

(define-key vterm-mode-map (kbd "C-q") #'vterm-send-next-key)

```



This can be useful for controlling an application running in the terminal, such

as Emacs or Nano.



## Fonts



You can change the font (the _face_) used in a vterm with the following code:



```elisp

(add-hook 'vterm-mode-hook

          (lambda ()

            (set (make-local-variable 'buffer-face-mode-face) 'fixed-pitch)

                 (buffer-face-mode t)))

```



Where instead of `'fixed-pitch` you specify the face you want to use. The

example reported here can be used to force vterm to use a mono-spaced font (the

`fixed-pitch` face). This is useful when your default font in Emacs is a

proportional font.



In addition to that, you can disable some text properties (bold, underline,

reverse video) setting the relative option to `t` (`vterm-disable-bold`,

`vterm-disable-underline`, or `vterm-disable-inverse-video`).



You can use another font for vterm buffer



``` elisp

(add-hook 'vterm-mode-hook

          (lambda ()

               (set (make-local-variable 'buffer-face-mode-face) '(:family "IosevkaTerm Nerd Font"))

               (buffer-face-mode t))

```

## Blink cursor



When `vterm-ignore-blink-cursor` is `t`, vterm will ignore request from application to turn on or off cursor blink.



If `nil`, cursor in any window may begin to blink or not blink because `blink-cursor-mode`

is a global minor mode in Emacs, you can use `M-x blink-cursor-mode` to toggle.



## Colors



Customize the following faces to your liking. It is possible to specify

different colors for foreground and background via the `:foreground` and

`:background` attributes.



- vterm-color-black

- vterm-color-red

- vterm-color-green

- vterm-color-yellow

- vterm-color-blue

- vterm-color-magenta

- vterm-color-cyan

- vterm-color-white

- vterm-color-bright-black

- vterm-color-bright-red

- vterm-color-bright-green

- vterm-color-bright-yellow

- vterm-color-bright-blue

- vterm-color-bright-magenta

- vterm-color-bright-cyan

- vterm-color-bright-white



## Directory tracking and Prompt tracking



`vterm` supports _directory tracking_. If this feature is enabled, the default

directory in Emacs and the current working directory in `vterm` are synced. As a

result, interactive functions that ask for a path or a file (e.g., `dired` or

`find-file`) will do so starting from the current location.



And `vterm` supports _prompt tracking_. If this feature is enabled, Emacs knows

where the prompt ends, you needn't  customize `term-prompt-regexp` any more.

Then you can use `vterm-next-prompt` and `vterm-previous-prompt`

moving to end of next/previous prompt. The default keybinding is `C-c C-n` and `C-c C-p`.



And `vterm-beginning-of-line` would move the point to the first character after the

shell prompt on this line. If the point is already there, move to the beginning of the line.

The default keybinding is `C-a` in `vterm-copy-mode`.



And `vterm--at-prompt-p` would check whether the cursor is at the point just after

the shell prompt.



Directory tracking and Prompt tracking requires some configuration, as the shell has to be

instructed to share the relevant information with Emacs. The following pieces of

code assume that you have the function `vterm_printf` as defined in section

[shell-side configuration](#shell-side-configuration).



For `zsh`, put this at the end of your `.zshrc`:



```zsh

vterm_prompt_end() {

    vterm_printf "51;A$(whoami)@$(hostname):$(pwd)"

}

setopt PROMPT_SUBST

PROMPT=$PROMPT'%{$(vterm_prompt_end)%}'

```



For `bash`, put this at the end of your `.bashrc`:



```bash

vterm_prompt_end(){

    vterm_printf "51;A$(whoami)@$(hostname):$(pwd)"

}

PS1=$PS1'\[$(vterm_prompt_end)\]'

```



For `fish`, put this in your `~/.config/fish/config.fish`:



```fish

function vterm_prompt_end;

    vterm_printf '51;A'(whoami)'@'(hostname)':'(pwd)

end

functions --copy fish_prompt vterm_old_fish_prompt

function fish_prompt --description 'Write out the prompt; do not replace this. Instead, put this at end of your file.'

    # Remove the trailing newline from the original prompt. This is done

    # using the string builtin from fish, but to make sure any escape codes

    # are correctly interpreted, use %b for printf.

    printf "%b" (string join "\n" (vterm_old_fish_prompt))

    vterm_prompt_end

end

```



Here we are using the function `vterm_printf` that we have discussed above, so make

sure that this function is defined in your configuration file.



Directory tracking works on remote servers too. In case the hostname of your

remote machine does not match the actual hostname needed to connect to that

server, change `$(hostname)` with the correct one. For example, if the correct

hostname is `foo` and the username is `bar`, you should have something like



```bash

HOSTNAME=foo

USER=baz

vterm_printf "51;A$USER@$HOSTNAME:$(pwd)"

```



## Message passing



`vterm` can read and execute commands. At the moment, a command is

passed by providing a specific escape sequence. For example, to evaluate



```elisp

(message "Hello!")

```



use



```sh

printf "\e]51;Emessage \"Hello\!\"\e\\"

# or

vterm_printf "51;Emessage \"Hello\!\""

```



The commands that are understood are defined in the setting `vterm-eval-cmds`.



As `split-string-and-unquote` is used the parse the passed string, double quotes

and backslashes need to be escaped via backslash. A convenient shell function to

automate the substitution is



`bash` or `zsh`:



```sh

vterm_cmd() {

    local vterm_elisp

    vterm_elisp=""

    while [ $# -gt 0 ]; do

        vterm_elisp="$vterm_elisp""$(printf '"%s" ' "$(printf "%s" "$1" | sed -e 's|\\|\\\\|g' -e 's|"|\\"|g')")"

        shift

    done

    vterm_printf "51;E$vterm_elisp"

}

```



`fish`:



```fish

function vterm_cmd --description 'Run an Emacs command among the ones been defined in vterm-eval-cmds.'

    set -l vterm_elisp ()

    for arg in $argv

        set -a vterm_elisp (printf '"%s" ' (string replace -a -r '([\\\\"])' '\\\\\\\\$1' $arg))

    end

    vterm_printf '51;E'(string join '' $vterm_elisp)

end

```



Now we can write shell functions to call the ones defined in `vterm-eval-cmds`.



```sh

find_file() {

    vterm_cmd find-file "$(realpath "${@:-.}")"

}



say() {

    vterm_cmd message "%s" "$*"

}

```



Or for `fish`:



```fish

function find_file

    set -q argv[1]; or set argv[1] "."

    vterm_cmd find-file (realpath "$argv")

end



function say

    vterm_cmd message "%s" "$argv"

end

```



This newly defined `find_file` function can now be used inside `vterm` as



```sh

find_file name_of_file_in_local_directory

```



If you call `find_file` without specifying any file (you just execute `find_file` in your shell),

`dired` will open with the current directory.



As an example, say you like having files opened below the current window. You

could add the command to do it on the lisp side like so:



```elisp

(push (list "find-file-below"

            (lambda (path)

              (if-let* ((buf (find-file-noselect path))

                        (window (display-buffer-below-selected buf nil)))

                  (select-window window)

                (message "Failed to open file: %s" path))))

      vterm-eval-cmds)

```



Then add the command in your `.bashrc` file.



```sh

open_file_below() {

    vterm_cmd find-file-below "$(realpath "${@:-.}")"

}

```



Then you can open any file from inside your shell.



```sh

open_file_below ~/Documents

```



## Shell-side configuration files



The configurations described in earlier sections are combined in

[`etc/`](./etc/). These can be appended to or loaded into your user

configuration file. Alternatively, they can be installed system-wide, for

example in `/etc/bash/bashrc.d/`, `/etc/profile.d/` (for `zsh`), or

`/etc/fish/conf.d/` for `fish`.



When using vterm Emacs sets the environment variable INSIDE_EMACS in the subshell to ‘vterm’.

Usually the programs check this variable to determine whether they are running inside Emacs.



Vterm also sets an extra variable EMACS_VTERM_PATH to the place where the vterm library is installed.

This is very useful because when vterm is installed from melpa the Shell-side configuration files are

in the EMACS_VTERM_PATH inside the /etc sub-directory. After a package update, the directory name changes,

so, a code like this in your bashrc could be enough to load always the latest version of the file

from the right location without coping any file manually.



```sh

if [[ "$INSIDE_EMACS" = 'vterm' ]] \

    && [[ -n ${EMACS_VTERM_PATH} ]] \

    && [[ -f ${EMACS_VTERM_PATH}/etc/emacs-vterm-bash.sh ]]; then

	source ${EMACS_VTERM_PATH}/etc/emacs-vterm-bash.sh

fi

```



## Frequently Asked Questions and Problems



### How can I increase the size of the scrollback?



By default, the scrollback can contain up to 1000 lines per each vterm buffer.

You can increase this up to 100000 by changing the variable

`vterm-max-scrollback`. If you want to increase it further, you have to edit the

file `vterm-module.h`, change the variable `SB_MAX`, and set the new value for

`vterm-max-scrollback`. The potential maximum memory consumption of vterm

buffers increases with `vterm-max-scrollback`, so setting `SB_MAX` to extreme

values may lead to system instabilities and crashes.



### How can I automatically close vterm buffers when the process is terminated?



There is an option for that: set `vterm-kill-buffer-on-exit` to `t`.



### The package does not compile, I have errors related to `VTERM_COLOR`.



The version of `libvterm` installed on your system is too old. You should let

`emacs-libvterm` download `libvterm` for you. You can either uninstall your

libvterm, or instruct Emacs to ignore the system libvterm. If you are compiling

from Emacs, you can do this by setting:



```elisp

(setq vterm-module-cmake-args "-DUSE_SYSTEM_LIBVTERM=no")

```



and compile again. If you are compiling with CMake, use the flag

`-DUSE_SYSTEM_LIBVTERM=no`.



### `` doesn't kill previous word.



This can be fixed by rebinding the key to what `C-w` does:



```elisp

(define-key vterm-mode-map (kbd "")

    (lambda () (interactive) (vterm-send-key (kbd "C-w"))))

```



### `counsel-yank-pop` doesn't work.



Add this piece of code to your configuration file to make `counsel` use

the correct function to yank in vterm buffers.



```elisp

(defun vterm-counsel-yank-pop-action (orig-fun &rest args)

  (if (equal major-mode 'vterm-mode)

      (let ((inhibit-read-only t)

            (yank-undo-function (lambda (_start _end) (vterm-undo))))

        (cl-letf (((symbol-function 'insert-for-yank)

               (lambda (str) (vterm-send-string str t))))

            (apply orig-fun args)))

    (apply orig-fun args)))



(advice-add 'counsel-yank-pop-action :around #'vterm-counsel-yank-pop-action)

```



### How can I get the local directory without shell-side configuration?



We recommend that you set up shell-side configuration for reliable directory

tracking. If you cannot do it, a possible workaround is the following.



On most GNU/Linux systems, you can read current directory from `/proc`:



```elisp

(defun vterm-directory-sync ()

  "Synchronize current working directory."

  (interactive)

  (when vterm--process

    (let* ((pid (process-id vterm--process))

           (dir (file-truename (format "/proc/%d/cwd/" pid))))

      (setq default-directory dir))))

```



A possible application of this function is in combination with `find-file`:



```elisp

(advice-add #'find-file :before #'vterm-directory-sync)

```



This method does not work on remote machines.



### How can I get the directory tracking in a more understandable way?



If you looked at the recommended way to set-up directory tracking, you will have

noticed that it requires printing obscure code like `\e]2;%m:%2~\a` (unless you

are using `fish`).



There is another way to achieve this behavior. Define a shell function, on a

local host you can simply use



```sh

vterm_set_directory() {

    vterm_cmd update-pwd "$PWD/"

}

```



On a remote one, use instead



```sh

vterm_set_directory() {

    vterm_cmd update-pwd "/-:""$USER""@""$HOSTNAME"":""$PWD/"

}

```



Then, for `zsh`, add this function to the `chpwd` hook:



```zsh

autoload -U add-zsh-hook

add-zsh-hook -Uz chpwd (){ vterm_set_directory }

```



For `bash`, append it to the prompt:



```bash

PROMPT_COMMAND="${PROMPT_COMMAND:+$PROMPT_COMMAND; }vterm_set_directory"

```



Finally, add `update-pwd` to the list of commands that Emacs

is allowed to execute from vterm:



```elisp

(add-to-list 'vterm-eval-cmds '("update-pwd" (lambda (path) (setq default-directory path))))

```



### When evil-mode is enabled, the cursor moves back in normal state, and this messes directory tracking



`evil-collection` provides a solution for this problem. If you do not want to

use `evil-collection`, you can add the following code:



```elisp

(defun evil-collection-vterm-escape-stay ()

"Go back to normal state but don't move

cursor backwards. Moving cursor backwards is the default vim behavior but it is

not appropriate in some cases like terminals."

(setq-local evil-move-cursor-back nil))



(add-hook 'vterm-mode-hook #'evil-collection-vterm-escape-stay)

```



## Related packages



- [vterm-toggle](https://github.com/jixiuf/vterm-toggle): Toggles between a

  vterm and the current buffer

- [multi-libvterm](https://github.com/suonlight/multi-libvterm): Multiterm for emacs-libvterm



## Appendix



### Breaking changes



Obsolete variables will be removed in version 0.1.



#### August 2022

* `vterm-send-C-[a-z]` `vterm-send-M-[a-z]` `vterm-define-key`

 `vterm-send-{up/down/left/right/prior/next/meta-dot/meta-comma/ctrl-slash}`

 were obsolete, please use `vterm-send` or `vterm-send-key` or

 `vterm--self-insert` instead.



#### October 2020



* `vterm-disable-bold-font` was renamed to `vterm-disable-bold` to uniform it

   with the other similar options.



#### July 2020



* `vterm-use-vterm-prompt` was renamed to `vterm-use-vterm-prompt-detection-method`.

* `vterm-kill-buffer-on-exit` is set to `t` by default.



#### April 2020



* `vterm-clear-scrollback` was renamed to `vterm-clear-scrollback-when-clearning`.

* `vterm-set-title-functions` was removed. In its place, there is a new custom

  option `vterm-buffer-name-string`. See

  [vterm-buffer-name-string](vterm-buffer-name-string) for documentation.