Introduction

This is a collection of small shell utilities that connect to a local Emacs server.

These utilities make it easy for shell commands and scripts to integrate with Emacs. This is especially useful when running from a shell from within an Emacs instance.

• e - execute an elisp expression and print the result
• ebuf - send stdin into an Emacs buffer
• ecat - send the content of an Emacs buffer to stdout
• ecompile - execute a command using Emacs compile
• ereg - manipulate the kill ring and registers
• erun - run a command in an Emacs comint buffer
• emerge - merge files using Ediff on Emacs

These tools connect to Emacs through a UNIX or TCP socket created by the Emacs server

Getting Started

Assuming that you have golang tools installed, just run:

make 
sudo make install

and you'll find the commands in /usr/local/bin.

To install it in your home directory instead, run:

DESTDIR=~/ make install

Commands

e

e evaluates a lisp expression and prints the result.

The main difference between e and emacsclient -eval is that e cleans up the result, so you'll get:

$ e '(concat "hello " "world")'
hello world

and not "hello world". This kind of output is easier to use in shell scripts.

epipe

epipe allows piping short command output to the shell and large command output into an Emacs buffer.

For example:

git log | epipe

outputs the first 15 lines in the shell, then redirects the rest to a new buffer.

You can configure the number of lines to output in the shell, the buffer name and whether a new buffer is created every time. See the output of epipe -help for details.

epipe makes a good default pager, when running in a shell inside of emacs. Try adding the following to your .bashrc:

if [ -n "$INSIDE_EMACS" ]; then
  export PAGER="epipe --limit 30" 
  export GIT_PAGER="epipe --limit 10 '*git*'"
fi

In some cases, Emacs can detect the type of content that is piped and choose the appropriate major mode. This can be configured on the Emacs side. See the documentation of magic-mode-alist in the section Auto Major Mode of the Emacs manual.

For example, with the following snippet in ~/.emacs.d/init.el:

(push '("^diff" . diff-mode) magic-mode-alist)

Emacs will detect diffs and format them nicely with diff-mode when using git diff | epipe

ebuf

ebuf allows piping the output of shell commands to a new Emacs buffer.

Example:

grep cat ~/.bash_history | ebuf cats

ebuf works like epipe, with the difference that even short command output are put into the buffer.

erun

erun tells Emacs to execute a command inside of a buffer. This can be more convenient than piping and works with interactive commands.

You can customize the buffer name, whether a buffer is created, whether the buffer is selected and whether the point stays at the beginning or follows the end of the file. See the output of erun -help for details.

Example:

erun grep cat ~/.bash_history

ecat

ecat outputs a buffer to stdout. The buffer is identified by its name.

This lets you process the content of buffers from inside the shell.

Example:

ecat cats | wc -l

ereg

ereg can both set and read the content of the kill ring.

ereg alone outputs the content of the kill ring, while ereg -i puts stdin into the kill ring.

Example:

$ echo hello | ereg -i
$ ereg
hello

Add the name of a register to read or write to a register instead of the kill ring.

ecompile

ecompile executes a command in a compilation buffer.

Example:

ecompile make

emerge

emerge helps resolve conflicts using Ediff.

The command starts an Ediff merge session and waits for the user to end the session, usually by pressing q in the buffer "Ediff Control Panel".

If the session ends with all conflicts resolved, the merge is reported as successful to the caller. If there are conflicts left, the session is reported as failed.

Normally, emerge reuses Emacs current frame, to change that specify either -tty to run Ediff in the current terminal or -frame to open a new frame.

The tool also installs the following command bindings to the Ediff control panel:

C-c C-k : ends the Ediff session unsuccessfully

C-c C-c : ends the Ediff session successfully

To use it with git, add the following to ~/.gitconfig:

[mergetool "ediff"]
    cmd = /usr/local/bin/emerge -local "$LOCAL" -remote "$REMOTE" -base "$BASE" -merged "$MERGED"
    trustExitCode = true

[merge]
    tool = ediff

To use it with Mercurial, add the following to ~/.hgrc:

[ui]
merge = emacs

[merge-tools]
emacs.executable = /usr/local/bin/emerge
emacs.args = -local $local -remote $other -base $base -merged $output

Connection to Emacs

These tools communicate with Emacs through a UNIX socket. The default matches the default socket name created by server-start.

If you use more than one server, you'll need to either pass it to the command, using the argument -socket-name or set the env variable EMACS_SOCKET_NAME, or -server-file and EMACS_SERVER_FILE respectively if using a TCP server.

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License GPL2