Why I use Emacs

Introduction

These days at the lab, I have been having friendly arguments with a colleague about the merits of Emacs vs Vim. A long time ago (2001-2006) I was a power Vim user, I could move to any place in a file without thinking about it, I left ":wq" in all the files that I edited with other editors and my .vimrc was easily the most complex configuration file I had on my system. I won't get into the details of why I switched (long story short: the languages I was interested in back then, Common Lisp and OCaml, had way better Emacs modes than Vim did), instead I'll explain some of the reasons why I have been using Emacs for the past 8 years and why I see myself sticking with it for many years to come.

Emacs: The Editor

There is a joke that goes "Emacs is a great operating system: it just lacks a good text editor." It's usually uttered by Vim users who have the only editor that I consider is superior at manipulating text than Emacs, and by people using other editors (e.g. Atom, Sublime Text) who parrot the Vim users.

The truth is that Emacs is a great text editor if you learn to use it properly. Beyond the basic movement commands of moving one character/word/sentence/paragraph at a time, Emacs has many commands that make manipulating text great:

• sexp manipulation: Emacs is written in Lisp, and it has commands that work at the s-expression level. Great for selecting the current form you are currently within, moving to the enclosing one, to the left/right siblings, etc.
• advanced search and replace functionality: like all editors, Emacs can search for strings, and it can also search for regular expressions. When you do a search-replace command, the power of regular expressions is often very helpful to perform complex manipulations, and if that's not enough, you can even inject Lisp code in your replacement!
• Macros: if search and replace is not powerful enough, or requires too much hackery to work properly, one possible avenue is to use macros. Macros allow you to record your keystrokes and replay them again later. If you were careful during the initial recording to use general commands, it's possible to apply a macro to an entire file to successfully modify it. I use macros practically every day when I use Emacs.
• hippie-expand: very often, you will want to write a word that already exists somewhere: either in the current buffer, in another buffer, perhaps it's a filename, etc. hippie-expand is a command that will search many sources of inputs and try to complete the partial word that you have written. I use it so much that when I am in another program, I feel paralyzed.
• M-x align: often when you write or program, you have multiple consecutive lines that have the same structures, but differ in some of the content. For example, a tabular section in LaTeX. M-x align and M-x align-regex are two commands that can help you get the different parts of your text properly aligned. Nice text is always better to look at.
• Rectangular editing: though definitely lacking compared to Vim's visual block mode, rectangular editing is a feature that is too often lacking in editors. How cool is it to add, delete or modify text on multiple lines interactively?
• M-x ibuffer: ibuffer allows you to see which files are currently opened (more generally, which buffers exist in Emacs) and manipulate them. One manipulation you can do is mark some of them and give an edition command to perform in all of them, usually a search and replace. This is great when you want to modify multiple files.
• evil-mode: if at the end of the day, you still find Vim to be a superior program for manipulating text, you can install evil-mode, a Vim emulation layer that will give you the vast majority of Vim's commands inside Emacs. Many editors offer a Vim compatibility mode, but it's always very superficial, and beyond insert and normal mode, there's not much to see. Evil-mode on the other hand supports more Vim commands than I know! You can use text objects, visual block editing, complex ex commands (e.g. :norm works), macros, Vim's undo commands, etc. If your favorite command is not yet there, it is highly possible that it is being worked on right now. Several Vim plugins are being ported to evil-mode too (e.g. nerd commenter, matchit). If you are a Vim user, I encourage you to give it a try, it's not a toy, it's very serious, very polished project.

Emacs: The Operating System

Going back to the joke "Emacs is a great operating system: it just lacks a good editor", it turns out that the part about Emacs being a great operating system is also true!

• dired-mode: dired-mode allows you to manipulate directories and files on your file system from within Emacs. You can create directories, copy/move/delete files, you can rename files, etc. When I am not manipulating files with my shell, I am using dired-mode.
• Embedded shells: Emacs has many ways to give you access to a shell: M-x shell for a basic shell, M-x eshell for a shell that integrates nicely with Emacs and Lisp, M-x ansi-term for an actual terminal emulator. If you have keyboard shortcuts for those commands (I use C-x m for M-x shell and C-x M for M-x ansi-term), you can very quickly switch between your editing task and your shell.
• Package manager: Emacs has modes, Lisp programs that give it new capabilities. It used to be that you had to find, download and compile these modes yourself. With the newly-added package-manager, M-x list-packages, and repositories such as MELPA, installing new capabilities for Emacs is as easier than using apt-get.
• System utilities: Emacs has many utilities to interact with a Unix system. Some that I use often are M-x man to view man pages, M-x ispell to spell-check a document and M-x grep to perform a grep on the file system from within Emacs and visit the results (modes also exist for users of ack and ag). You can find many more such utilities in Emacs's package manager.
• ido-mode: ido is an Emacs mode to make switching buffers easier. Whereas most modern editors use tabs to represent every opened files, in Emacs you can do without such a waste of screen estate. Instead, ido allows you to quickly switch from one buffer to another by typing just a part of the buffer's name you want to switch to. It supports flex-matching, and also integrates with opening and writing files. Even with hundreds of buffer, ido makes switching between them easy and efficient.
• Tramp: tramp allows an Emacs user to open files over network (ftp, ssh, and many others) or to open files using sudo. Very useful if you want to open a file on a remote machine without having to launch a terminal and connect with ssh.
• Info: Emacs has an entire documentation built-in, info, and using C-h i you can find information on a great number of subjects: the Emacs manual, the Emacs Lisp reference, documentation on the many modes installed on your system, etc.
• Themes: Emacs has a large collection of color themes to match your mood. Some of my personal recommendations: if you want something light, Leuven is nice; I am also a fan of phoenix-dark-pink if I want something dark and with low contrast.
• IRC: Some people aren't really into using a tool for 17 different tasks and prefer to use one tool per task. I mostly do too, however IRC is different; I use it to discuss with other members of my lab, and if the conversation was in another program, I might miss it because I am focused on my programming task. I use Circe in Emacs, and when someone talks on a channel, a small notification appears in the mode-bar, and the shortcut C-c C-SPC allows me to quickly switch to the channel, read what's going on, and switch back to my work.

Emacs: The Development Environment

I am a programmer, and Emacs features for development are what really drew me in. Emacs has support for practically all known programming languages, and very often its support is better than anything else you can find. One great advantage of this wide support is that you can use Emacs for all your programming needs, whatever the language may be, and benefit from the intimate knowledge you have of your editor. To me, it seems like a much better deal than knowing in less details one editor per language. It's also less annoying (and less memory hungry) if you happen to work in many different languages at once (e.g. Python, Django templates, HTML, CSS, JavaScript).

• Modes for languages: all programming modes usually feature syntax highlighting and auto indenting, something pretty much standard in all programmers' editors, but it's worth mentioning that you'll find such support for more languages in Emacs than in any other editor. The programming modes can also offer extra functionality specific to the language, such as switching between .ml and .mli for OCaml or shifting a block left/right for Python.
• Compiler integration: using the M-x compile command allows you to interact with a build system such as make. Emacs is able to parse the output of make and allows you to move back-and-forth between the different errors and warnings. Support for integrating with ant or maven is available in the package manager.
• REPL integration: many languages have a REPL, a read-eval-print loop that allows the programmer to use the language interactively. Emacs has great support for REPLs, allowing you to run them inside Emacs and to send commands from your source file buffers to the REPL process.
• Debugger support: although I'm not a big fan of the debugger support in Emacs, gud is a mode that allows Emacs to become a bug-finding station.
• Tags: tags are a mechanism to index the different identifiers in a program; Emacs uses this information to allow the programmer to find the declaration site of a function for example. If ctags is too basic for you, Emacs also has support for more advanced tools, such as cscope and GNU global.
• Magit: Git took the programming world by storm a few years ago, and today it is the de facto standard VCS tool used by millions of programmers. Magit is Emacs's user-friendly interface to Git; not all commands are supported, however the basic flow of git (committing, pushing, pulling, viewing logs, branching, tagging, etc.) are all supported. Magit is the reason I switch from Mercurial to Git.
• fly-make: fly-make allows Emacs to run a compiler/interpreter in the background to detect syntax and semantic errors in your program and report them immediatly with squiggly lines. I'm not a big fan, but if that's the kind of thing you are into, go for it!

Emacs: The Lisp Machine

Emacs is really a Lisp machine: all modes are written in Lisp and you can configure the editor using Lisp commands. Being a Lisp Machine is also what allows all the cool modes mentioned above: when you need something, you can always use Emacs Lisp to code it. Although Emacs Lisp is not the greatest language in the world, it is still a powerful and sophisticated language that can be used to transform a problem you have into a solution that an entire community can use.

This unbounded extensibility is the reason why GNU Emacs is still used today, more than 30 years after its initial release. If a piece of software cannot keep up with the times, it will eventually be replaced by something better. By giving the users of Emacs the power to fit it to do anything they please, the authors of Emacs have ensured that the people most interested in keeping it up to date can do so.

Conclusion

Emacs may not be for everyone, I accept that, but I strongly suggest that you give it a try. Not so that you can adopt it, but so that when you go back to your preferred editor, you can bring something new and fresh to their development.

I'll probably still be using Emacs in 2024, and if I start having Emacs pinkie syndrome, I can always just enable evil-mode :)