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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 5h

would any of you folks be interested in reading an explanation of Git's data model I'm working on? (with the goal of including it in Git's official documentation)

if so, reply to this and I'll DM you a link!

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 2d

git usage question: if you use `git pull` and `git push`, how do you usually use them?

possible answers include:

- just run `git push` and `git pull` with no arguments (other than --rebase or --ff-only etc)
- always specify remote/branch with `git push origin main` and `git pull origin main`
- […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 9d

@ddr oh to be clear my plan is to totally avoid referencing the concept of a DAG in any way, not to explain it with a metaphor :)

Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 9d

I'm thinking of trying to add an explanation of Git's core data model (commits / branches / references) to Git's official documentation, but where should it go?

curious about where you would think to look for such a thing

here are the current docs: https://git-scm.com/docs

Git - Reference

git-scm.com

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 9d

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

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 13d

I've been using a workflow for making Git's man pages clearer which is

1. Ask Git users for feedback on the existing man pages (using a somewhat janky custom tool I built)
2. Make changes based on that feedback
3. Propose the changes

it seems to be going well!

(2/?)

Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 13d

related to the Git cheat sheet I mentioned last week https://git-scm.com/cheat-sheet, I'm thinking of making some changes to the official Git glossary (https://git-scm.com/docs/gitglossary), to make it easier to look up what terms like "object" or "reference" mean in Git

I need some test […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 14d

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!

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 22d

where this came from is that I made a Git cheat sheet a while back at https://wizardzines.com/git-cheat-sheet.pdf

and then I found out that the folks who make the official Git website are super open to contributions and thought "... wait, the website doesn't have a cheat sheet, I could just […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 22d

added a cheat sheet to the official Git website https://git-scm.com/cheat-sheet

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 22d

@hacks4pancakes if it's any consolation, as someone who's lived in Canada my entire life I still have no idea what units container sizes are likely to be in (it really depends on the kind of food that's in the container!) and would just try asking for a "small" or "medium" or something

Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 22d

more "how do you use this git feature" questions: do you ever use `git reset --soft`? What do you use it for?

(note: --soft is not the default)

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 23d

if you're interested in helping with Project Improve Git Documentation, I'm still looking for beta readers! Here's a signup form: https://forms.gle/QP5NUcvPQV6W7DCJ9

I'd love signups from anyone who uses Git on the command line, isn't 100% comfortable with it, and who would be interested in […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 23d

more git docs changes: got some changes to the `git add` man page merged into Git! I've been having a lot of fun working on making git's documentation a little easier to read.

https://github.com/git/git/commit/4065e482f7fe349505877b45b6a5edaa12522f2d

(2/?)

Merge branch 'je/doc-add' · git/git@4065e48

Documentation for "git add" has been updated. * je/doc-add: doc: rephrase the purpose of the staging area doc: git-add: simplify discussion of ignored files doc: git-add: clarify i...

github.com

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 23d

@MacBalance just published this zine about Git in 2024! :) https://wizardzines.com/zines/git/

How Git Works

wizardzines.com

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 23d

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

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 25d

@nafmo is the idea that you have only 1 change in progress at a time so you just use the `main` branch for your changes instead of putting them on a branch?

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 25d

@jasonkarns I think i’m missing something here, usually when I make an OSS contribution I create a new branch for my changes, so i would pull from the main branch and push to my feature branch (and my feature branch would have a different upstream from the main branch)

I guess you do something […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 25d

another slightly obscure git question: have you ever used the “pushremote“ option in Git so that you can push a branch to a different remote than you pull from? Why?

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Reposted by Julia Evans

Mastodon @mastodon.mastodon.social.ap.brid.gy · 27d

Today, we’re ready to show you the upcoming quote posts feature in more detail. We’ve put together a blog post with examples of how quote posts will work on Mastodon, ahead of early access on our own servers next week 💬 Full launch to come, in Mastodon v4.5 […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · 27d

more weird git stuff : I'm trying to explain why "git pull origin main" will merge `main` into the current branch, but 'git push origin main' will NOT push the current branch to `main` (instead AFAICT it pushes the local "main" branch to the remote "main", no matter what your current branch is) […]

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · Sep 8

@Kudusch yeah definitely! this page talks about that https://wizardzines.com/comics/meet-the-terminal-emulator/

meet the terminal emulator

wizardzines.com

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · Sep 8

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.

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · Sep 8

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

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Julia Evans @b0rk.social.jvns.ca.ap.brid.gy · Sep 3

for a long time I've been ignoring git GUI tools ("I can just use the command line! it's fine!) but recently I've been needing to do a lot of repeated "edit the commit message of the commit 3 commits ago", and doing that with `git rebase -i` is annoying.

with lazygit I can just scroll to the […]

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