Julia Evans
LightNews LightNews
b0rk.social.jvns.ca.ap.brid.gy
Julia Evans
@b0rk.social.jvns.ca.ap.brid.gy
570 followers 0 following 710 posts
programming and exclamation marks

I have DMs muted from people I don’t follow.

[bridged from https://social.jvns.ca/@b0rk on the fediverse by https://fed.brid.gy/ ]
Posts Replies Media Videos
b0rk.social.jvns.ca.ap.brid.gy
@gnomon the drywall saw was great
October 26, 2025 at 11:41 PM
b0rk.social.jvns.ca.ap.brid.gy
just added the MEGA TERMINAL CHEAT SHEET from "The Secret Rules of the Terminal" to our list of posters at https://wizardzines.com/#posters
October 20, 2025 at 3:22 PM
b0rk.social.jvns.ca.ap.brid.gy
TERM

https://wizardzines.com/comics/term/

(from The Secret Rules of the Terminal, out now! https://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
October 14, 2025 at 3:09 PM
b0rk.social.jvns.ca.ap.brid.gy
meet the terminal emulator https://wizardzines.com/comics/meet-the-terminal-emulator/

(from The Secret Rules of the Terminal, out now! (https://wizardzines.com/zines/terminal/)
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
September 29, 2025 at 4:15 PM
b0rk.social.jvns.ca.ap.brid.gy
stty

https://wizardzines.com/comics/stty/

(from The Secret Rules of the Terminal, out now! https://wizardzines.com/zines/terminal/)
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!
September 24, 2025 at 3:21 PM
b0rk.social.jvns.ca.ap.brid.gy
TERM

https://wizardzines.com/comics/term/

(from "The Secret Rules of the Terminal", out now! https://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
September 15, 2025 at 3:07 PM
b0rk.social.jvns.ca.ap.brid.gy
finally (after literally everyone else *) I got my print copy of The Secret Rules of the Terminal!

(* or I hope after literally everyone else, please send us a support email if you didn't get your preordered copy yet!)
The Secret Rules of the Terminal, by Julia Evans - The cover illustration depicts three people doing arcane terminal magic in a temple with a smoking censer in the background. Each of the three people has curly brown hair and light brown skin. They are all wearing dresses, billowing cloaks, and utility belts with keyboard symbols on them. The one on the left holds a palette of paints and a brush. The one on the right has a staff with a $ symbol on it and a starfish at the top. The one in the centre has a sword and is reading from a book whose cover says “>_” and “./”, which rests on a lectern with a smiling snake wrapped around it.
September 8, 2025 at 3:14 PM
b0rk.social.jvns.ca.ap.brid.gy
meet the TTY driver

https://wizardzines.com/comics/meet-the-tty-driver/

(from "The Secret Rules of the Terminal", out now!)
the TTY driver is the most obscure part of the system You almost never need to think about it, but when I’ve wanted to do something weird (like put a terminal in a web browser) understanding the driver is SO USEFUL when you start your terminal emulator, it asks the OS to create a “pseudoterminal pair” which is a pair of two files terminal emulator <-> TTY <-> TTY driver <-> TTY <-> program a “TTY” is the program’s side of the pair programs use it to: communicate with the terminal emulator by reading/writing bytes configure the TTY driver (more on the next page!) Run tty fo see the current TTY! the TTY driver is why Ctrl+C does the same thing relatively consistently program: you press Ctrl+C, I send a signal! well, unless the program tells me it wants the raw bytes! some things the TTY driver is in charge of (you might think “these are unrelated” and you’d be right) storing the terminal window’s size sending a SIGHUP signal when you close your terminal a basic mode for entering text called “canonical mode” pausing the output and confusing you when you press Ctrl+S tracking which process is in the “foreground” and sending what you type there
September 8, 2025 at 3:07 PM
b0rk.social.jvns.ca.ap.brid.gy
terminal colours

https://wizardzines.com/comics/colours/

(from "The Secret Rules of the Terminal", out now!)
your terminal emulator has 16 configurable colours normal bright black 0 0 red 1 1 green 2 2 yellow 3 3 blue 4 4 purple 5 5 cyan 6 6 white 7 7 these are called “ANSI colours” you can configure them in your terminal emulator’s settings OR run a script that prints escape codes to magically set up your colours https://wzrd.page/scripts (my favourite way!) programs can use ANSI colours by printing an escape code echo -e "\033[34m blue text" 3 means “normal fg colour” 4 means “blue” the default ANSI colours often have bad contrast ls --color often displays directories in ANSI “blue” which can look like this: [bar of illegibly dark text against a dark background, which says “can you read this?”] ANSI “yellow” on white also often has bad contrast “minimum contrast” Picking ANSI colours which always have good contrast is impossible. the only real solution is to use a terminal emulator which has a “minimum contrast” feature (like iTerm or kitty) which will fix contrast issues usually if a program is writing to a pipe, it’ll disable colours $ grep blah file.txt | less grep, represented by a box with a smiley face: better turn off colours so that I don’t accidentally show someone `^[[34ntext here]
September 2, 2025 at 3:05 PM
b0rk.social.jvns.ca.ap.brid.gy
has anyone seen a man page with a nice approach to providing a summary for a command with a lot of command line options, like this?

having something like [-0468openrsyncPRSTWVabcdefghiklmnopqrtuvxyz] always feels silly (it's almost the whole alphabet!) but I […]

[Original post on social.jvns.ca]
openrsync [-0468BCDEFHILOPRSTWVabcdefghiklmnopqrtuvxyz] [-e program] [-f filter] [--address=sourceaddr] [--append] [--backup-dir=directory] [--bwlimit=limit] [--cache | --no-cache] [--checksum-seed=NUM] [--chmod=MODE] [--compare-dest=directory] [--compress-level=NUM] [--contimeout=seconds] [--copy-dest=directory] [--copy-unsafe-links] [--del] [--delay-updates] [--delete-before] [--delete-during] [--delete-delay] [--delete-after] [--delete-excluded] [--exclude pattern] [--exclude-from=file] [--extended-attributes] [--files-from=filespec] [--force] [--ignore-errors] [--ignore-existing] [--ignore-non-existing] [--include pattern] [--include-from=file] [--inplace] [--keep-dirlinks] [--link-dest=directory] [--list-only] [--max-delete=MAX] [--max-size=size] [--min-size=size] [--modify-window=sec] [--no-implied-dirs] [--no-motd] [--numeric-ids] [--partial] [--partial-dir=DIR] [--password-file=pwfile] [--port=service] [--progress=VER] [--protocol] [--read-batch=file] [--remove-source-files] [--rsync-path=program] [--safe-links] [--size-only] [--sockopts=sockopts] [--specials] [--stats] [--suffix=suffix] [--super] [--timeout=seconds] [--only-write-batch=file | --write-batch=file] source ... directory
August 26, 2025 at 4:52 PM
b0rk.social.jvns.ca.ap.brid.gy
job control

https://wizardzines.com/comics/job-control/

(from The Secret Rules of the Terminal, which is out now!)
your shell lets you run many programs (“jobs”) in the same terminal tab programs can either be: foreground background stopped (which is more like “paused”) & runs a program in the background for example I like to convert 100 files in parallel like this: for i in `seq 1 100` do convert $i.png $i.jpg & done jobs lists backgrounded & stopped jobs $ jobs [1] Running python blah.py & [2] Stopped vim use the numbers to bring them to the foreground or background (like fg %2), kill them (kill %2), or disown them when you close a terminal tab all jobs are killed with a SIGHUP signal you can stop this with disown or by starting the program with nohup: disown %1 (job number goes here) nohup my_program & a trick to kill programs if Ctrl+C doesn’t work press Ctrl+Z to stop the program run kill %1 to kill it (or kill -9 %1 if you’re feeling extra murderous) a little flowchart Three boxes, labelled “running in foreground”, “stopped”, and “running in background” Ctrl+Z goes from “running in foreground” to “stopped” fg goes from “stopped” to “running in foreground” fg goes from “running in background” to “running in foreground” bg goes from “stopped” to “running in background”
August 26, 2025 at 3:20 PM
b0rk.social.jvns.ca.ap.brid.gy
editing text in a REPL

https://wizardzines.com/comics/editing-text-in-a-repl/

(from "The Secret Rules of the Terminal", which is out now! wizardzines.com/zines/terminal)
editing text in a REPL doesn’t always work little stick figure, horrified: when I press my ARROW KEYS it just prints out [[D??? what? this is because every program has fo implement text editing itself terminal program author, represented by a nonplussed looking stick figure with medium length straight hair, thinking: but I just want arrow keys to work?? shouldn’t that be automatic? unix, represented by a box with a smiley face: NOPE you gotta do it you do gef a few things automatically backspace (occasionally backspace won’t work and you have to use Ctrl+H instead) Ctrl+W (delete word) Ctrl+U (delete line) (see page 25 for what “automatically” means) REPLs mostly have the same keyboard shortcuts there’s a very popular library called “readline”, and everyone either uses it or imitates how it works for example Ctrl+A (“go to beginning of line”) comes from readline rlwrap adds readline keyboard shortcuts for example on my machine the dash shell doesn’t use readline but you can make it better by running: rlwrap dash built in programs on Mac don’t use readline (for example sq1ite3) this is probably because readline is GPL licensed They use libedit which is worse. I like to install a sqlite version with readline support and use that instead.
August 19, 2025 at 3:08 PM
b0rk.social.jvns.ca.ap.brid.gy
how your terminal handles mouse clicks

https://wizardzines.com/comics/the-mouse

(from "The Secret Rules of the Terminal", which is out now! https://wizardzines.com/zines/terminal)
when you click in the terminal, it can either be handled by your terminal emulator (represented by a box with a winky cursor face and little arms and legs) (good if you want to copy text) or the program (represented by a box with a smiley face) (lots of programs have mouse support!) programs can tell the terminal emulator to let them handle the mouse program: if there’s a mouse click, send me escape codes to tell me where it was! terminal emulator: okay! I’ll disable all my usual mouse functions like “selecting text”! this is called “mouse reporting” some programs that have mouse support tmux: resize a pane! right-click for a menu! htop: click to sort columns! micro: text editor with good mouse support vim: click on the tab bar! and lots more! (lazygit, mc, zellij, btop…) how to force the terminal emulator to handle the mouse: unhappy stick figure with short curly hair, thinking: ugh no I don’t want to focus that pane, I want to COPY SOME TEXT!!! could be something else too, it depends on your terminal emulator the scroll wheel In some programs (like less) the scroll wheel does the same thing as pressing up/down arrow keys really fast terminal emulator: UP UP UP UP UP UP UP UP UP UP UP UP in other programs (like lazygit) it uses “mouse reporting” to report where your mouse was when you scrolled other mouse features your terminal emulator might have Shift+click (or something) to open a link in a browser Alt+click (or maybe Option)
August 12, 2025 at 3:13 PM
b0rk.social.jvns.ca.ap.brid.gy
just noticed Bite Size Command Line came out 7 years ago, I still sometimes forget the syntax for lsof and have to look it up at https://wizardzines.com/comics/lsof/ :)

https://wizardzines.com/zines/bite-size-command-line/
August 5, 2025 at 3:29 PM
b0rk.social.jvns.ca.ap.brid.gy
it's really fun to see the reviews of "The Secret Rules of the Terminal" come in, it looks like the zine is helping people in the way I hoped it would!

you can get it here: https://wizardzines.com/zines/terminal/
As a longtime terminal user on macOS and various Linux distributions, I've developed muscle memory for repetitive tasks and commands. But sometimes they "just don't work," and I would never really know why. Julia's zine, like all of her work, helps bridge the gap between "stuff I picked up along the way" and "what works".
July 17, 2025 at 12:27 PM
b0rk.social.jvns.ca.ap.brid.gy
we ran a Wizard Zines reader survey and it's interesting to see that 75% of people who buy the zines have been programming for 10+ years

When I imagine a typical reader I always imagine someone who's been programming (in some capacity) for at least 5-10 years […]

[Original post on social.jvns.ca]
37% - 30+ years 39.5% - 10-30 years 13.6% - 5-10 years 10% - under 5 years
July 4, 2025 at 3:52 PM
b0rk.social.jvns.ca.ap.brid.gy
periodic reminder that if you want to get "The Secret Rules of the Terminal" (or any other zine!) and you're in a country with a weaker currency than the US (India, Brazil, etc), there's a discount to make the zines more affordable. You can see it in action […]

[Original post on social.jvns.ca]
"If you need it, please use code XXX at checkout to get 70% off the regular price"
June 26, 2025 at 7:24 PM
b0rk.social.jvns.ca.ap.brid.gy
delighted to announce that my new zine "The Secret Rules of the Terminal" is out today!!

You can get it for $12 USD here: https://wizardzines.com/zines/terminal
The Secret Rules of the Terminal, by Julia Evans - The cover illustration depicts three people doing arcane terminal magic in a temple with a smoking censer in the background. Each of the three people has curly brown hair and light brown skin. They are all wearing dresses, billowing cloaks, and utility belts with keyboard symbols on them. The one on the left holds a palette of paints and a brush. The one on the right has a staff with a $ symbol on it and a starfish at the top. The one in the centre has a sword and is reading from a book whose cover says “>_” and “./”, which rests on a lectern with a smiling snake wrapped around it.
June 24, 2025 at 4:52 PM
b0rk.social.jvns.ca.ap.brid.gy
it's happening! "The Secret Rules of the Terminal" is coming out tomorrow!

here's the table of contents:
1. SHELL cast of characters meet the shell PATH PATH tips history job control filename tips stdin/stderr/stdout redirects 2. TERMINAL EMULATOR meet the terminal emulator escape cdoes colours the mouse copy & paste TERM 3. PROGRAMS types of programs less editing text in REPLs keyboard shortcuts 4. TTY DRIVER meet the TTY driver stty canonical mode
June 23, 2025 at 8:00 PM
b0rk.social.jvns.ca.ap.brid.gy
here's the final version of the "redirects cheat sheet" draft I posted a while back!

("The Secret Rules of the Terminal is finished! 95 beta readers have read it! the copy editor is done! technical review is done! the illustrator has made the cover! It's […]

[Original post on social.jvns.ca]
cmd > file.txt cmd >> file.txt cmd < file.txt cmd 2> file.txt cmd > file.txt 2>&1 cmd1 | cmd2 cmd1 2>&1 | cmd2 three gotchas: 1. 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 and redirect to the same file" seared into my memory. 2. 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' 3. cmd 2>&1 > file.txt doesn't write both stdout and stderr to file.txt. Instead, do: cmd > file.txt 2>&1 panel 3: cat vs < I almost always prefer to do: cat file.txt | cmd instead of cmd < file.txt it usually works fine & it feels better to me using cat can be slower if it's a GIANT file though panel 4: &> and &| some shells support &> and &| to redirect/pipe both stdout and stderr (also some shells use |& instead of &|)
June 20, 2025 at 7:53 PM
b0rk.social.jvns.ca.ap.brid.gy
I've still never gotten into `fzf` (and maybe I never will!) but I think it's really cool that you can use a fzf 1-liner to make things like this little UI for reviewing git commits

https://jvns.ca/til/fzf-preview-git-commits/
View with files on the left and diff for that file on the right
June 17, 2025 at 3:57 PM
b0rk.social.jvns.ca.ap.brid.gy
just got the cover art for The Secret Rules of the Terminal and it's looking so good! it features these very good shell earrings

if you want to get an email when the zine comes out you can sign up here! https://wizardzines.com/zine-announcements/
person with their hair in a spirally updo with earrings shaped like a shell
June 10, 2025 at 3:10 PM
b0rk.social.jvns.ca.ap.brid.gy
was just reminded of how much I love the debugging manifesto poster that Inner Loop Press designed for Wizard Zines, you can get it for $20 US + shipping here: https://store.wizardzines.com/products/poster-debugging-manifesto

I'm SO delighted with how it […]

[Original post on social.jvns.ca]
June 4, 2025 at 3:24 PM
b0rk.social.jvns.ca.ap.brid.gy
I think I have finally managed to articulate this very fundamental but slightly counterintuitive fact about how shell redirection works
when you redirect, the shell opens the file BEFORE the program starts sudo echo blah > file.txt first I'll open file.txt... THEN I'll run sudo echo blah this is why file.txt isn't opened as root!
May 23, 2025 at 6:26 PM
b0rk.social.jvns.ca.ap.brid.gy
i enjoy this flowchart explaining how bash decides whether to use .bashrc or .bash_profile https://blog.flowblok.id.au/2013-02/shell-startup-scripts.html, mostly because it makes me understand better why I could never understand how the 2 config files worked when I used bash
May 15, 2025 at 3:35 PM