Ben Whitley github.com/purplg Just someone who loves computers.

I have a tendency to move fast (sorry!), so please remind me to slow down if I go too fast.

Emacs is a Lisp engine that was turned into an editor. The core is written in C but most of it is written in Emacs Lisp. This enables you to change pretty much anything about it at runtime.

It's harder to find things Emacs can't do.

(eww "https://google.com")

(eww "https://www.gnu.org/software/emacs/")

(eww "https://orgmode.org")

Browse and manage files. This is actually a package called dirvish, but it just a prettifies dired and adds features.

An interactive markup language. Notes, TODOs, documents, whatever.

Probably the best frontend to Git out there, albeit a bit of a learning curve.

Supports pretty much every git function there is.

Makes rebasing super easy. Much easier than trying to do it from the command line. Especially when editing commit history.

Assign some variable in session "one"

session_name = "session-one"

Assign some variable in session "two"

session_name = "session-two"

Print out session_name in session "one"

print(session_name)

Print out session_name in session "two"

print(session_name)

Here we name a block greeting. The stdout of this block will be saved into a variable with this name.

a = "Hello!"
print(a)

For bash block, we store the output of the greeting block into a variable named input.

echo $input

For emacs-lisp block, we store the output of the greeting block into a variable named input.

(s-trim (reverse input))

Now let's flip it back around with bash

echo ${input} | rev

First we create a new code block that creates a list of number-words from 0 to 9.

return ["Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"]

Using Python in a different block, we iterate through each number and print the length

(re-search-forward "^[[:space:]]*\\(#\\+\\)\\([^[:space:]]+\\).*" nil t)
(match-string 2)

for number in numbers:
  print(f"{number:>5}: {len(number)}")

Or we can use bash, for some reason

for number in ${numbers[@]}; do
  printf "%5s: %u\n" ${number} $(echo ${number} | wc -c)
done

But enough about programming. Let's talk about configuration management.

A very popular way people configure Emacs (or other software) is using a Literate Config. A Literate Config is a bunch of code blocks that get tangled into files.

#+SETUPFILE: https://fniessen.github.io/org-html-themes/org/theme-readtheorg.setup

Tramp allows editing remote files with support for many transport backends, include SSH, FTP, sudo (???), docker (and podman), etc.

SPC f f /ssh:user@host:

SPC f f /sudo:/etc/passwd

You can even chain transports together:

/ssh:user@remotehost|sudo:root@remotehost:/path/to/file

You can even read from serial devices. This is great because since you can read and write from the comfort of Emacs!

Start fake tty sockets

socat -d -d pty,raw,echo=0 pty,raw,echo=0

Read

/usr/bin/cat < /dev/pts/1

Write

echo "Hello" > /dev/pts/2

(serial-term "/dev/pts/1" 9600)

(serial-term "/dev/pts/2" 9600)

A little self-promotion, but it's a really good example of Emacs uses.

Home Assistant is open source home automation software that acts as a hub for connection all your smart devices together.

Questions? Comments? I could talk about this all day