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Julia Evans

@b0rk.jvns.ca

41K followers 320 following 6.7K posts

programming and exclamation marks blog: jvns.ca zines: wizardzines.com

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Julia Evans @b0rk.jvns.ca · 10h

one way I might think of it is that 1% people are good at building developer tooling for themselves and others and I’m not. Like I have the technical skills to build this script but I never would have thought of it github.com/mjdominus/gi...

Julia Evans @b0rk.jvns.ca · 10h

I’ve never understood how it’s possible to customize your dev environment to suit you in a really micro way

I’m not a good UX designer. If i’m trying to customize something in my editor it’s probably because another editor has an interaction pattern that I like that I’m trying to copy.

Julia Evans @b0rk.jvns.ca · 11h

I’m not sure about the 1% thing. I’ve actually tried to switch away from vim to an IDE (atom, sublime, VS Code) many times, but it never stuck because I like how stable and fast vim is.

I do think that as I get older I have less and less patience for tinkering with configuration.

Julia Evans @b0rk.jvns.ca · 1d

TERM

wizardzines.com/comics/term/

(from The Secret Rules of the Terminal, out now! wizardzines.com/zines/terminal)

different terminal emulators use different escape codes

terminal emulator 1: if you print out ESC[2J I’ll clear the screen!

terminal emulator 2: for me it’s ESC[HESC[J!
your system has a database called “terminfo” with escape codes in it

how if plays out when you press Ctrl+L to clear the screen:

program, with a little heart over it, thinking:
ah, she wants fo clear the screen! I’ll look up how to do that in the terminfo database…

(on my machine, the database is in /usr/share/terminfo)

program: ESC[HESC[J

terminal emulator, thinking: ok, clearing the screen!
how programs know what terminal you’re using: TERM

your terminal emulator sets the TERM environment variable when it starts

fun fact: terminal emulators often say they’re “xterm-256color” even if they’re not
this can break when SSHing into an old system with a new terminal emulator

(in a VERY annoying way)

happy little stick fiture: I am using ghostty

program, with a little heart over it: NOPE never heard of it
some ways to fix TERM

install the terminfo file for your terminal emulator on the system
use a different terminal emulator
just set TERM=xterm-256color, it’ll often sort of work

Julia Evans @b0rk.jvns.ca · 2d

thanks these are very good helix posts, learned about some great features

Julia Evans @b0rk.jvns.ca · 5d

thanks, I appreciate having that to refer to if I end up going back to neovim!

Julia Evans @b0rk.jvns.ca · 5d

fixed that one too, thanks!

Julia Evans @b0rk.jvns.ca · 5d

here are some notes based on a very vague memory of my attempts to set this up 5 months ago: gist.github.com/jvns/b1dba4e...

Julia Evans @b0rk.jvns.ca · 5d

my issues with vim.lsp.config may have been related to refusing to have any Lua code in my neovim config, not sure. I still only use a .vimrc

Julia Evans @b0rk.jvns.ca · 5d

i’ll try to come up with some notes! i did try vim.lsp.config unsuccessfully but I don’t remember what happened, I can try to dig it up.

I’ve kind of given up on trying out new vim plugins unless there’s an “obvious” contender that everyone agrees is the best so i didn’t try any search alternatives

Julia Evans @b0rk.jvns.ca · 5d

why do you ask?

Julia Evans @b0rk.jvns.ca · 5d

thanks, fixed!

Julia Evans @b0rk.jvns.ca · 5d

notes on switching to Helix from vim jvns.ca/blog/2025/10...

Julia Evans @b0rk.jvns.ca · 6d

watching this was such a fun way to learn a little about Ethernet

TracketPacer @tracketpacer.bsky.social · 6d

what happens if u cut 4 wires out of an ethernet cable & then plug it into yr PC

Julia Evans @b0rk.jvns.ca · 8d

redirects

wizardzines.com/comics/termi...

(from "The Secret Rules of the Terminal", out now! wizardzines.com/zines/termin...)

redirect to a file:

cmd > file.txt terminal emulator into program, program out to file.txt, error out to terminal emulator
append to a file:

cmd >> file.txt terminal emulator into program, program out to file.txt (append mode), error out to terminal emulator
send a file to stdin:

cmd < file.txt file.txt into program, program out and err to terminal emulator
redirect stderr to a file:

cmd 2 > file.txt terminal emulator into program, program out to nowhere, err out to file.txt
redirect stdout AND stderr:

cmd > file.txt 2>&1 terminal emulator into program, out and err to file.txt
pipe stdout:

cmd1 | cmd2 terminal emulator into program 1, 1 out to program 2 via pipe, 2 out to command line, program 2 out 1 and 2 to terminal emulator
pipe stdout AND stderr:

cmd1 2>&1 | cmd2 terminal emulator into program 1, 1 and 2 out to program 2 via pipe, program 2 out 1 and 2 to terminal emulator
three gotchas

cmd file.txt > file.txt will delete the contents of file.txt some people use set -o noclobber (in bash/zsh) to avoid this

but I just have “never read from redirect to the same file” seared into my memory.

sudo echo blah > /root/file.txt doesn’t write to /root/file.txt as root. Instead, do:

echo blah | sudo tee /root/file.txt or sudo sh -c 'echo blah > /root/file.txt'

cmd 2>&1 > file.txt doesn’t write both stdout and stderr to file.txt. Instead, do: cmd > file.txt 2>&1

cat vs <

I almost always prefer to do:

cat file.txt | cmd

instead of

cmd < file.txt

it works fine & it feels better to me

using cat can be slower if if’s a GIANT file though
&> and &|

some shells support &> and &| to redirect/pipe both stdout and stderr

(also some shells use |& instead of &|)

Julia Evans @b0rk.jvns.ca · 16d

it's silly because "this is why it feels good to me to do those things" was right there

Julia Evans @b0rk.jvns.ca · 16d

thanks!

Julia Evans @b0rk.jvns.ca · 16d

I use Affinity Designer right now! I used to use the Notability ipad app before that, and the Squid Android app before that

Julia Evans @b0rk.jvns.ca · 16d

meet the terminal emulator wizardzines.com/comics/meet-...

(from The Secret Rules of the Terminal, out now! (wizardzines.com/zines/termin...)

your terminal emulator has two main jobs

turn your actions (typing & clicking) into bytes and send them
receive bytes and display them visually

Illustration of a terminal emulator, with a winking cursor face, and a program, represented by a box with a smiley face. The program has a heart above it, and there are arrows going back and forth between them labelled “bytes”
a little bit of history

it’s called an “emulator” because in the 80s a “terminal” was a separate machine from the computer

Illustration of a bulky old monitor, with a keyboard attached with a spiral cord, and a wire running to a panl of buttons and displays, labelld “mainframe”. There are arrows going back and forth between them labelled “bytes”

We still use the same 80s protocol!
what are these “bytes”?

the bytes are either:

text (like cat blah.txt)
escape codes (for example to tell the terminal what colour to display the text in)
control characters example Ctrl+C is the byte 3)

it’s in charge of copy and paste

your terminal emulator lets you select text and copy/paste it (usually with Ctrl+Shift+C (Linux) or Cmd+C (Mac))

(copy & paste tips on page 18!)
it manages colours and fonts!

some terminal emulators come with a big theme library of different colourschemes!

if yours doesn’t, this site has colourschemes for many terminal emulators: iterm2colorschemes.com
fun fact: how Ctrl-X gets translated to bytes

Ctrl-A => 1
Ctrl-B => 2
...
Ctrl-Z => 26

Ctrl is the only modifier key I trust in the terminal, all of the others can work differently depending on the situation

Julia Evans @b0rk.jvns.ca · 19d

ah yeah I imported some tweets from Twitter using
@en.blueark.app and it causes more confusion than I'd like. If you click on it you can see the "original" date it was posted (in 2013)

Julia Evans @b0rk.jvns.ca · 21d

stty

wizardzines.com/comics/stty/

(from The Secret Rules of the Terminal, out now! wizardzines.com/zines/termin...)

your TTY driver has configuration

you can see how it’s configured by running:

stty -a

for example it print out the current window size!
Ctrl+S

by default, pressing Ctrl+S wi(( freeze your terminal (and Ctrl+Q wi(( unfreeze) I have never wanted this in my life, you can turn it off with stty -ixon (fish turns it off by default)

###fun fact: changing Ctrl+C technically you can use stty to set a different keyboard shortcut for Ctrl+C, (ike “u”

stty intr u

this is extremely chaotic and I can’t imagine a reason that I would ever do this though
programs have to configure the TTY driver to get friendly features

developer: I want arrow keys to work in my program!

other person: better tell the TTY driver to turn off canonical mode! (more on the next page)
the TTY driver’s settings are called “termios settings”

for the gnarly details:

man termios

but if you’re writing a terminal program libraries like readline or ncurses will handle setting up the TTY driver
panel 6

smiling stick figure with short curly hair: I’ve only needed to use stty once in the last 20 years and I mostly don’t understand its output but I think it’s a fun view into terminal internals!

Julia Evans @b0rk.jvns.ca · 28d

haha i’m going to tell everyone that’s the reason

Julia Evans @b0rk.jvns.ca · 29d

it's in there! :)

Julia Evans @b0rk.jvns.ca · 29d

added a cheat sheet to the official Git website

(with a lot of help from other folks who work on the website)

git-scm.com/cheat-sheet

Git Cheat Sheet

Julia Evans @b0rk.jvns.ca · Sep 15

TERM

wizardzines.com/comics/term/

(from "The Secret Rules of the Terminal", out now! wizardzines.com/zines/termin...)

different terminal emulators use different escape codes

terminal emulator 1: if you print out ESC[2J I’ll clear the screen!

terminal emulator 2: for me it’s ESC[HESC[J!
your system has a database called “terminfo” with escape codes in it

how if plays out when you press Ctrl+L to clear the screen:

program, with a little heart over it, thinking:
ah, she wants fo clear the screen! I’ll look up how to do that in the terminfo database…

(on my machine, the database is in /usr/share/terminfo)

program: ESC[HESC[J

terminal emulator, thinking: ok, clearing the screen!
how programs know what terminal you’re using: TERM

your terminal emulator sets the TERM environment variable when it starts

fun fact: terminal emulators often say they’re “xterm-256color” even if they’re not
this can break when SSHing into an old system with a new terminal emulator

(in a VERY annoying way)

happy little stick fiture: I am using ghostty

program, with a little heart over it: NOPE never heard of it
some ways to fix TERM

install the terminfo file for your terminal emulator on the system
use a different terminal emulator
just set TERM=xterm-256color, it’ll often sort of work