:title: EShell
:date: 2026-04-29
:tags: emacs
:identifier: 20260429T185129
:signature: 5=7=2

Eshell
======

To quote the `manual <https://www.gnu.org/software/emacs/manual/html_mono/eshell.html>`__

.. pull-quote::

   Eshell is a shell-like command interpreter implemented in Emacs Lisp.
   It invokes no external processes except for those requested by the user.
   It is intended to be an alternative to the IELM REPL for Emacs *and* with an interface similar to
   command shells such as ``bash``, ``zsh``, ``rc``, or ``4dos``.


Custom Commands
---------------

Here are some custom eshell commands I have implemented.
Big thanks to `this episode <https://youtu.be/M6o1N2kfmuc>`__ of Álvaro Ramírez's Bending Emacs series for showing me this was possible.

``eshell/http-server``
^^^^^^^^^^^^^^^^^^^^^^

A utility command that uses `start-process <https://www.gnu.org/software/emacs/manual/html_node/elisp/Asynchronous-Processes.html#index-start_002dprocess>`__ to run Python's ``http.server`` module in the background.

.. code-block:: elisp
   :project: emacs
   :filename: lisp/alc-eshell.el
   :template: elisp-module

   (require 'alc-python)

   (defun eshell/http-server (dirname &rest args)
     "Use `start-process' to invoke a background Python http.server in
   the given DIRNAME"
     (let ((port (alc-eshell--get-port-number)))
       (start-process (format "http:%s" port)
                      (format "*http-server<%s>*" dirname)
                      (or python-shell-interpreter "python")
                      "-m" "http.server"
                      "-d" dirname
                      (format "%s" port))
        (browse-url (format "http://localhost:%s" port))))


   (defun alc-eshell--get-port-number ()
     (alc-python-one-liner "
   import socket

   s = socket.socket()
   s.bind(('', 0))
   print(s.getsockname()[1], end = '')
   s.close()"))

Where